I love the fact that when the puzzle popped up I exclaimed (like hundreds of others I expect) "I'm thinking Phistomefel Ring" and seconds later you say "My first thought is Phistomefel" You and Mark have been such good Sudoku teachers these past few years 👍
This guy has done the impossible and created videos that are great for putting you to sleep as well as great for midday mental stimulation! Incredible!
One is the tone and flow, which is soothing and calming; the other is the math and problem solving which is both exciting and stimulating. You have summed up Simon perfectly.
@@margaretsinclair6697 I particularly love the usually cracked "Hello!" in the beginning of all of his videos. As if it's the first word he's said all day :D
It makes me so happy that you explain things for new viewers each time they occur. Not long ago I was a new viewer and would have been completely lost without your explanations. It’s an absolute joy to watch you solve!
I have been following this channel for around three years, and every time I watch you two take the time to explain a technique I smile and appreciate it. I needed it, and I know it is helpful for anyone new to the channel. Thank you for continuing to keep this channel approachable. :D
It's beautiful. And there are other ways to look at it too. Check this out imgur.com/a/IREk7o3 see the descriptions on each image for an explanation. It took me a long time to understand the set theory behind how Simon explains it, because it's all about messing with individual sets of the digits 1 to 9. Whereas the explanation I linked doesn't require messing with any sets of the digits. It's just comparing a 4-set to a 5-set and getting rid of the overlap and then a single set.
I'm new to sudoku in general, let alone all these weird rule sudokus.... but I've been watching the channel long enough to actually, in fact, know these simple tricks. Took me 104 minutes, but I'm thrilled!
Because of you, Simon and this channel, I'm trying to insert "Bobbins" into my cursing vernacular. I will even allow my little 2 yr old say that if she feels the need to exclaim at or because of anything. =)
Every time i watch you prove phisotmefel rings when they come up i always believe the proof, but it still astounds me that it actually ends up working out like that.
This was a great puzzle! After stuffing up twice (because I read the rules as having a knight's move restriction rather than a king's move restriction), I finally spotted the trick to break in, and it was relatively smooth sailing from there. What a beautiful design, and not too difficult a puzzle but so satisfying to solve!
Hey, SImon! Love the videos everyday. Just wanted to shout out that I finally got my last star in your thermo app! My only suggestion for improvement is related to the fact that you can't undo after you switch to check for errors. It would be incredibly helpful to still be able to undo after finding mistakes, because then you can learn from the error you made.
I am utterly amazed. You can place every 9 in the puzzle without marking a single cell or placing a single other digit. The central 9 is forced by the arrow sums. The other arrows are forced to be 9 sums by Phistomephel's ring. The ring must contain exactly two sets of the digits 1 to 8 due to the geometry constraints, eliminating 9 from all the cages, and the king's move constraint eliminates one of the two remaining options for 9's in boxes 1, 3, 7, and 9.
@w The arrow geometry doesn't allow for anything else. There are four unique pairs of digits. Two copies of each originating from the center sum. I colored them to prove the theory to myself, there are two possible arrangements, with symmetrical variants, but either way, the possible pairs force just one copy of each pair into the sums for the outer arrows, any other option would violate the king's move or diagonal constraints.
I used to listen to podcasts but when I fell asleep I never knew where I was and then I had to listen to parts again and again. With cracking the cryptic there's a new video every night that I find really exciting and interesting to watch but when I fall asleep I also don't mind that I haven't seen the ending. I honestly love this channel so much and have recommended it to an embarrassing amount of people ( even forced my drunk friends to watch you with me)
Fabulous puzzle with another great solve from Simon, and LOVE the outro! Thank you for such all round entertainment tonight: both logical/practical and creative :)
Oh. My. Word. I did it in 24 minutes flat, once I learned about that ring rule. That's the best I've ever done attempting a puzzle off this channel. This is one of those few times where plugging in every single possible digit for the arrows around the central nine is actually beneficial.
That interruption was unfortunate. Simon lost track of the logic he used to place those 3s and 6s, and I'm pretty sure he could have gotten other digits by rotating that deduction around the ring. Also, Simon missed the chance to say his car committed sudoku. Edit: Ah, I see he did come back to that technique. That's what I get for commenting mid-video.
46 min. Needed help from the first 23 min of the vid. My brain had a very hard time tracking and scanning. It was such a clever puzzle. You needed every rule, in so many different ways. Simon - it was amazing how fast you blasted thru the end! Must have wanted to get back to your mechanic! ;-)
Took me 18 minutes to solve, Im surprised how fast I did it, guess I got lucky spotting everything, as it usually takes me around double the time of the videos. Great video as always!
About the Phistomefel ring and the 'secret' and repetitive tricks ( X wings and such), you could just explain the result and include a link to the demonstration in the description. It would make the videos' rythm much better and less annoying to recurring viewers. Also the fact that you include links to the proof would still maintain the possibility to understand and learn for new viewers so they would not be left out
I'd like some kind of sudoku-parody of Edwin Starr - War. The refrain always plays in my head when Simon finds something that leads nowhere "what is it good for? absolutely nothing!" 😁
I have learned so much from this channel! So I saw the Phistomophel ring right away but also enjoyed doing the maths to see that 18+18=36 and 36+36=72 to go along with 4*18=72, of course, and used that to figure the 9's all by myself! Just had to come back to the video to be reminded of the King's move constraint. :P And I should give credit to the triangular numbers for their ever-available assistance.
I was trying to give this a go myself. (Having never heard of the phistomafel ring). Had to get Simon to explain that, and quite a good job he did, I was able to solve my first cracking the cryptic sudoku. Time was 138:46
This was a great puzzle, difficult but approachable. I forgot the king's move and got stuck, but Simon reminded me before giving me any other logic and I jumped back to finish it off.
36:33. Nice one! Huge kudos to Aad for setting this puzzle and to CTC for teaching us cool techniques! I have no idea how long it would take me to solve this sudoku if I didn't know about Phistomofel ring :)
Man, after spending hours solving this without that ring trick its really disappointing how easy it looks using it. Would have been interesting to see a solve without being given those 9s
Funny how now, as a 28 old man wacthing a sudoku channel, I stumble across the man who introduced me to the weirdness of the internet during my teenage years. Life sure comes around ain't it? haha
@@drunkrazy Indeed, I had to do a double-check for the name to make sure it was actually him. Weird but definitely interesting/exciting to spot in the wild.
I literally posted a X diagonal sudoku with identical arrow construction in box 5 in the Discord server two days ago not knowing Aad van de Wetering had already created this masterpiece. Very very nice solve.
Simon discovering the secret to the puzzle and then forgetting it for a while because the phone rang reminds me of two things: Samuel Taylor Coleridge realised the poem Kubla Khan in a dream, then when he woke he set about writing it down, only to be interrupted by a man at the door and the poem left unfinished forever. The other was when Isaac Newton invited his friend Edmund Halley round to explain his theories of planetary motion, but when he came round Newton had lost the paper he’d written his theories down on. Simon, you’re in good company 😀
after reading the comments, i have come to a conclusion that im probably the only person who watches simon playing sudoku, quite frequently, not because i also play sudoku but just because i find it interesting to watch smart people do something that my dumb brain can’t comprehend :’D
30:01 ... it took me a moment to see the diagonal arrows along the blue lines. Nice puzzle! (Loved the pair of 1-8 sets that went around the Devil Ring)
One thing I figured out shortly after you mentioned the phistomefel ring was that the sudoku had EXACTLY 2 sets of the digits 1-8 in the phistomefel ring so as soon as you got your first digit in the phistomefel ring it was easy to find its second spot in the ring
I had a very different break-in (before I got stuck and watched the video till your break-in :-). Using the phistomefel ring, and the arrow logic, I was able to figure out that the 9's in the circles, and then with the kings move constraints, the remaining 9's. (Same as you did). Using the diagonals, I could figure out that there was a 7 in R3C3 or R3C7 (the top 2 corners of this Phistophemel ring). That places a 2 in the top 2 corners of box 5 and eliminates the 2 (by Kings move) from R3C5! As a result, I could place the 2 in R7C5 and 7 in R6C5. Similar logic (starting with the 3's) leads to a 6 in R5C3 and 3 in R5C4. I also had a bunch of pencil marks for possible positions of 3, and 7. (boxes 1, 3, 7, 9) I then watched you deduce the presence of the 6 in Box 3, bottom row (which was brilliant!) - which allowed me to resolve my pencil marks and place the 3's and 7's in the 4 corner boxes. After that, it resolved quite quickly. Watching your video, I felt that you did not use the diagonals as much as you could have.
ahhhh - because there are no 9's in the Phistomofel ring - so none in the 4 square cells in the corners -they are the same digits!! Thank you Linux203 - now I understand that!
Very pretty grid. 2 sets of 1-8 in the corners and the ring. Sets of 1-9 plus another 9 in the other 4 sets of 10 outside box 5. And a pretty outro too... :)
26:44 finish. Everything's coming up 9s! I was wondering if it would wind up two sets of each digit 1-8 in the corners, but couldn't prove it. Glad to see that it worked out that way!
At 27:15 you can make progress with the 11 sum in r7c7/r8c7/r9c7. Ask whether a 1 can be in those three cells - it can't, as all three see 6, 7 , 8, and 9, and thus you can't make 10 from the remaining two cells. This puts a 1 in box 9's 18 cage, whose remaining digits must add to 14. As there's a 9 in the box already, we see that the 18 cage is made up of 1368, putting 245 in the original r7c7/r8c7/r9c7 cells.
27:17 Simon just said that the triplet in column 7, box 9 adds up to 11, so C7R4 and C7R5 are a domino with 8 total, so must be a 1/7 pair, and C7R4 cannot be 1 because it puts an 8 on the arrow which is forbidden by the antiking constraint, so must be the 7 etc. [edit] 30:07 So, Simon got the 7 in C7R4 with much more beautiful logic than just column scanning. I love that man.
Simon, is it the case that the orthogonal arrows from the centre need to be the mirror images of the diagonal ones? It is the case in this puzzle but it's hard to prove that it has to be the case.
I may have overcomplicated this a little in my solve. I took some time to prove to myself that the red cells could not have any repeated digits in them (as that would lead to the repeated digits being "seen" along all four edges of the Phistomophel ring, where they would clash with the givens). I also spent a fair bit of time and effort trying to find a way to prove that the 18 cages had to have two pairs of digits that each summed to 9 (which I failed to do, but which turned out to be true in the end). My final time was a nice, round 50:00
Tip for the software: If you have a pencil mark in a bunch of places you want to get rid of without deleting the contents completely (this works for center or corner marks), highlight the cells or everything and hit the number. It will fill in the squares that don't have it, then hit the number AGAIN, and it will remove it from all cells. It works like "fill all, then erase all."
one thing that could work all around the grid, is when you placed 6 on box 6, @26:44, you asked than how much left for reach 45. and you've the answer, 11. than you could have done math in column 7, giving you a 7-1 pair right up to the 6. and that would have gave to you the remaining 3 digit in that column. since this puzzle is simmetric, i think you could have done the same all around the ring
I wish I'd seen how the cage totals force the arrow totals, but here's something I was pretty proud of spotting about the diagonals: the 3s and 7s have sort of an x-wing-ish behavior that gives us some digits. On the "forward slash" diagonal, 7s are restricted to r2c2 and r3c3. On the "backslash" diagonal, 7s are restricted to r8c2 and r3c7. Between the two diagonals, we know that there will be a 7 in either r3c3 or r3c7. Because of the arrows those possible 7s are on, we know that there must be a 2 in either r4c4 or r4c6. Therefore, because of the king's move restriction, we know that r3c5 cannot be 2. If r3c5 can't be 2, then r4c5 can't be 7, giving us a 7 at r5c6 and a 2 at r5c7. By the same logic, the possible 3s in r3c7 and r7c7 wind up giving us a 3 in r5c4 and a 6 in r5c3.
Quote of the day: "sorry, got interrupted there by my garage ringing to tell me my car has exploded again, so you have to excuse me when I cry silently"
Or: "we talk about Sudoku miracles all the time but what we just saw there was a true miracle where you press an F-key of some sort and it really does nearly break you"
Sheer class from Aad. He always sets such elegantly constructed puzzles. Rather than use the diagonals to place the 9s, it was easier to note that none of the cages could contain a 9 due to Phistomefel''s ring, and each 9 in a circle removed two of the three options in each corner box. After solving it very similarly to Simon, and in a similar time, I thought I'd try an experiment. I started again, placed the 9s, then filled all the remaining cells with 1-8. I then went through the puzzle, eliminating digits from wherever they were blocked by one rule or another. Then, using the remaining digits on each end of the arrows, I was able to make more eliminations. This left triples and quads all over the place, allowing further eliminations. The cages typically had only five or six different digits, so maths could work out which to eliminate. After that, it was just a quick mopping up. It took just over 20 minutes, so it was significantly quicker, but it did feel like I'd cheapened the puzzle and left me feeling a bit dirty.
I don't see it mentioned yet, but F5 refreshes the browser window. And as an extra, Ctrl + F5 will reload the page while updating the cache (or ignoring the cache depending on how you want to look at it)
@23:48. Goes to great lengths explaining the ring. Casually drops a 3 in R3C7 without mentioning king's move restrictions. I'm slow without my coffee :( took a little bit to figure out his logic.
About 70 minutes for me. I was really slow making progress on this one, at first due to misreading the king's move rile as a Knight's move and getting very confused, and then by trying to do later steps of the solve early. Really good puzzle, especially if you weren't being a doofus like me throughout the solve.
You should make a few videos about the techniques (The ring here, X-wings, etc), that way you wouldn't need to explain everything every time. Just put these videos in a playlist and link the playlist in the description.
42:24 for my solve. I did it a quite different way. After having spotted the logic with Phisomefel's ring, I just colored every cell in the central box and solved the colored sudoku. Maybe less efficient but very fun to do and not difficult at all.
After you figure out all the nines, the bottom right 18 box has an 8 inside, so the rest add up to 10. But in the box they are already has 7,8,9 so the 10 sum always have a 3, and it should be on the ninth row. From that is quite straight forward
Would it be worth doing a separate video on the Phistomefel ring, and linking to it when required? Just to save you the time explaining it every time, and so that people who have been watching since the early days don't have to keep hearing it?
I looked at the puzzle and found that in the middle cell there had to be a 7 and a 9. I concluded that the puzzle was impossible, still went back to the rules and realized that there is a kings move constraint and not a knight's move.
I didn't watch the whole video, but it does NOT require the phistomefel ring to solve (or bifurcation). Straight solve in 30:55, with no special techniques. Very cool puzzle.
I took a rather different (albeit much uglier) path; I got the 9s the same, then worked out where 3 and 7 went in the central box by reference to the diagonals (as certain positions would have ruled them out of one diagonal or the other) then worked out that each of the corner cages had to have a pair of digits adding to 9 meaning they had to be two pairs of digits each adding to 9, which I was then able to use to unroll the ring (by virtue of knowing certain digits had to not be on one side of the ring) then work out the rest of the puzzle from there.
I love the fact that when the puzzle popped up I exclaimed (like hundreds of others I expect) "I'm thinking Phistomefel Ring" and seconds later you say "My first thought is Phistomefel" You and Mark have been such good Sudoku teachers these past few years 👍
This guy has done the impossible and created videos that are great for putting you to sleep as well as great for midday mental stimulation! Incredible!
Yes - I use them for both.
Simon has a very soothing voice.
One is the tone and flow, which is soothing and calming; the other is the math and problem solving which is both exciting and stimulating.
You have summed up Simon perfectly.
@@margaretsinclair6697 I particularly love the usually cracked "Hello!" in the beginning of all of his videos. As if it's the first word he's said all day :D
It makes me so happy that you explain things for new viewers each time they occur. Not long ago I was a new viewer and would have been completely lost without your explanations. It’s an absolute joy to watch you solve!
I have been following this channel for around three years, and every time I watch you two take the time to explain a technique I smile and appreciate it. I needed it, and I know it is helpful for anyone new to the channel. Thank you for continuing to keep this channel approachable. :D
Every time I see Simon explain Phistomefel, it blows my mind. Even after watching for several months.
It's beautiful. And there are other ways to look at it too. Check this out imgur.com/a/IREk7o3 see the descriptions on each image for an explanation.
It took me a long time to understand the set theory behind how Simon explains it, because it's all about messing with individual sets of the digits 1 to 9. Whereas the explanation I linked doesn't require messing with any sets of the digits. It's just comparing a 4-set to a 5-set and getting rid of the overlap and then a single set.
@@CrixOMix That makes sooo much more sense to me. Thanks!!
CTC is easily the Highlight of day.
I'm new to sudoku in general, let alone all these weird rule sudokus.... but I've been watching the channel long enough to actually, in fact, know these simple tricks. Took me 104 minutes, but I'm thrilled!
Because of you, Simon and this channel, I'm trying to insert "Bobbins" into my cursing vernacular. I will even allow my little 2 yr old say that if she feels the need to exclaim at or because of anything. =)
Every time i watch you prove phisotmefel rings when they come up i always believe the proof, but it still astounds me that it actually ends up working out like that.
Ditto!
I love the excitement when he finishes every puzzle and gets the "Looks good to me".
Every time you tell the secret, I kinda do feel special.
Thank you for the guitar and singing outro, I always enjoy those so much!
This was a great puzzle! After stuffing up twice (because I read the rules as having a knight's move restriction rather than a king's move restriction), I finally spotted the trick to break in, and it was relatively smooth sailing from there. What a beautiful design, and not too difficult a puzzle but so satisfying to solve!
Hey, SImon! Love the videos everyday. Just wanted to shout out that I finally got my last star in your thermo app! My only suggestion for improvement is related to the fact that you can't undo after you switch to check for errors. It would be incredibly helpful to still be able to undo after finding mistakes, because then you can learn from the error you made.
I am utterly amazed. You can place every 9 in the puzzle without marking a single cell or placing a single other digit. The central 9 is forced by the arrow sums. The other arrows are forced to be 9 sums by Phistomephel's ring. The ring must contain exactly two sets of the digits 1 to 8 due to the geometry constraints, eliminating 9 from all the cages, and the king's move constraint eliminates one of the two remaining options for 9's in boxes 1, 3, 7, and 9.
@w The arrow geometry doesn't allow for anything else. There are four unique pairs of digits. Two copies of each originating from the center sum. I colored them to prove the theory to myself, there are two possible arrangements, with symmetrical variants, but either way, the possible pairs force just one copy of each pair into the sums for the outer arrows, any other option would violate the king's move or diagonal constraints.
I had the same realization, but I ended up not using that fact later.
@w I had trouble following the set logic also
The logic here is quite beautiful. I'm glad Simon uses that word because it's underused.
I used to listen to podcasts but when I fell asleep I never knew where I was and then I had to listen to parts again and again. With cracking the cryptic there's a new video every night that I find really exciting and interesting to watch but when I fall asleep I also don't mind that I haven't seen the ending. I honestly love this channel so much and have recommended it to an embarrassing amount of people ( even forced my drunk friends to watch you with me)
This was so fun. I just solved a puzzle and I used Phistomefel's theorem for the break-in. I'm very proud of this.
Very happy to have finished this one, even spotting the Phistomofel ring!
Fabulous puzzle with another great solve from Simon, and LOVE the outro! Thank you for such all round entertainment tonight: both logical/practical and creative :)
Oh. My. Word. I did it in 24 minutes flat, once I learned about that ring rule. That's the best I've ever done attempting a puzzle off this channel. This is one of those few times where plugging in every single possible digit for the arrows around the central nine is actually beneficial.
Do I KNOW the simple tricks... quite possibly.
Can I SPOT when the simple tricks are needed.... mmm, prolly not. Let's see.
_Edit: Nope._
I feel the same way... 😔
That interruption was unfortunate. Simon lost track of the logic he used to place those 3s and 6s, and I'm pretty sure he could have gotten other digits by rotating that deduction around the ring.
Also, Simon missed the chance to say his car committed sudoku.
Edit: Ah, I see he did come back to that technique. That's what I get for commenting mid-video.
He was noticeably derailed by the exploding car - but then who wouldn't be!
Ok... saving that screenshot. That face when the puzzle vanishes was priceless.
I love it when Simon amazes us with sudoku magic, makes us laugh and then sings us to sleep!
I am honored to know the secret. If only potential millionaires also knew it...
And I feel so special that I am one of the people who Simon told this too...
I'm going to be a very good friend of him to learn it as well
Those knowledge shows pretty much only deal with useless information, so I'm not surprised that she was unaware of this very useful information.
we _are_ the potential millionaires now!
Aad is just the best. His puzzles are a great balance of challenge, logic, and approachability.
I really like Sudokus that look aesthetically symmetrical before start and I can proceed somewhat symmetrically during the solve!
46 min. Needed help from the first 23 min of the vid. My brain had a very hard time tracking and scanning. It was such a clever puzzle. You needed every rule, in so many different ways. Simon - it was amazing how fast you blasted thru the end! Must have wanted to get back to your mechanic! ;-)
I am having so much fun with your Miracle Sudoku app. Thank you, and keep up the great work guys.
Took me 18 minutes to solve, Im surprised how fast I did it, guess I got lucky spotting everything, as it usually takes me around double the time of the videos. Great video as always!
That was absolutely gorgeous! Aad never disappoints!!
About the Phistomefel ring and the 'secret' and repetitive tricks ( X wings and such), you could just explain the result and include a link to the demonstration in the description.
It would make the videos' rythm much better and less annoying to recurring viewers.
Also the fact that you include links to the proof would still maintain the possibility to understand and learn for new viewers so they would not be left out
The first video of ctc I watched was a random suggestion and contained phistomefel but because you explained it so well I got hooked and subscribed
36:48 for me, I'm quite pleased with myself. I also thought "Phistomefel" when I saw the boxes, and caught on the arrows had to be 9.
Any one else want a full 3 to 5 min song from Simon?
PLEASE PLEASE
Make it about sudoku😁
I'd like some kind of sudoku-parody of Edwin Starr - War. The refrain always plays in my head when Simon finds something that leads nowhere "what is it good for? absolutely nothing!" 😁
Makes for a good Podcast outro.
I have learned so much from this channel! So I saw the Phistomophel ring right away but also enjoyed doing the maths to see that 18+18=36 and 36+36=72 to go along with 4*18=72, of course, and used that to figure the 9's all by myself! Just had to come back to the video to be reminded of the King's move constraint. :P
And I should give credit to the triangular numbers for their ever-available assistance.
I've been watching CTC for a while. This sudoku was my first I did, it was so enjoyable! Thanks for the content!
Hello simon! beautiful puzzle today. Loved the outro too 😂
I was trying to give this a go myself. (Having never heard of the phistomafel ring). Had to get Simon to explain that, and quite a good job he did, I was able to solve my first cracking the cryptic sudoku. Time was 138:46
A simpler proof for the ring: the ring sees all but the 4 corner boxes by sudoku. So the 4 celled cages have to equal the ring.
I don't think that proves the two sets have to be identical. Not every cell on the ring sees every cell outside of the corner boxes.
This was a great puzzle, difficult but approachable. I forgot the king's move and got stuck, but Simon reminded me before giving me any other logic and I jumped back to finish it off.
36:33. Nice one! Huge kudos to Aad for setting this puzzle and to CTC for teaching us cool techniques! I have no idea how long it would take me to solve this sudoku if I didn't know about Phistomofel ring :)
Man, after spending hours solving this without that ring trick its really disappointing how easy it looks using it. Would have been interesting to see a solve without being given those 9s
Yeah it’s a very useful trick to know for certain puzzles
Funny how now, as a 28 old man wacthing a sudoku channel, I stumble across the man who introduced me to the weirdness of the internet during my teenage years. Life sure comes around ain't it? haha
@@drunkrazy Indeed, I had to do a double-check for the name to make sure it was actually him. Weird but definitely interesting/exciting to spot in the wild.
Welcome to the world of puzzles. Where beautiful gimmicks and gimmes go hand in hand and beat your brain to death
OMG my worlds have collided! Cyriak does sudoku!
I literally posted a X diagonal sudoku with identical arrow construction in box 5 in the Discord server two days ago not knowing Aad van de Wetering had already created this masterpiece. Very very nice solve.
Great puzzle, and I loved the outro :-) really well done all around!
45:12 for me, it was fun seeing how the ring and the secret really came together in this puzzle
Fabulous fabulous puzzle! Entertaining enough that I was prepared to start over after making a misstep. Nailed it on the second attempt.
I never knew I should to have an opinion on how to label my rectangles…and now I’m having an existential crisis.
I can't stop laughing now, thanks 🤣🤣
Simon discovering the secret to the puzzle and then forgetting it for a while because the phone rang reminds me of two things: Samuel Taylor Coleridge realised the poem Kubla Khan in a dream, then when he woke he set about writing it down, only to be interrupted by a man at the door and the poem left unfinished forever. The other was when Isaac Newton invited his friend Edmund Halley round to explain his theories of planetary motion, but when he came round Newton had lost the paper he’d written his theories down on. Simon, you’re in good company 😀
after reading the comments, i have come to a conclusion that im probably the only person who watches simon playing sudoku, quite frequently, not because i also play sudoku but just because i find it interesting to watch smart people do something that my dumb brain can’t comprehend :’D
Nice outro 😀
30:01 ... it took me a moment to see the diagonal arrows along the blue lines.
Nice puzzle! (Loved the pair of 1-8 sets that went around the Devil Ring)
One thing I figured out shortly after you mentioned the phistomefel ring was that the sudoku had EXACTLY 2 sets of the digits 1-8 in the phistomefel ring so as soon as you got your first digit in the phistomefel ring it was easy to find its second spot in the ring
I had a very different break-in (before I got stuck and watched the video till your break-in :-).
Using the phistomefel ring, and the arrow logic, I was able to figure out that the 9's in the circles, and then with the kings move constraints, the remaining 9's. (Same as you did).
Using the diagonals, I could figure out that there was a 7 in R3C3 or R3C7 (the top 2 corners of this Phistophemel ring). That places a 2 in the top 2 corners of box 5 and eliminates the 2 (by Kings move) from R3C5! As a result, I could place the 2 in R7C5 and 7 in R6C5. Similar logic (starting with the 3's) leads to a 6 in R5C3 and 3 in R5C4.
I also had a bunch of pencil marks for possible positions of 3, and 7. (boxes 1, 3, 7, 9)
I then watched you deduce the presence of the 6 in Box 3, bottom row (which was brilliant!) - which allowed me to resolve my pencil marks and place the 3's and 7's in the 4 corner boxes. After that, it resolved quite quickly.
Watching your video, I felt that you did not use the diagonals as much as you could have.
As soon as you realize that all cells in the Phistomofel ring are on arrows, you know that no 9 can be in the four corners.
ahhhh - because there are no 9's in the Phistomofel ring - so none in the 4 square cells in the corners -they are the same digits!! Thank you Linux203 - now I understand that!
Very proud that I spotted phistomefel ring straight away ! X
Very pretty grid. 2 sets of 1-8 in the corners and the ring. Sets of 1-9 plus another 9 in the other 4 sets of 10 outside box 5. And a pretty outro too... :)
45:09 for my solve, without knowing the Phistomefel Ring trick, which is apparently taught in this video. I should come back to it and learn it.
I've never seen a ring before, thank you a lot!
Love your Damien Rice outros! ❤️
[@23:50]
After that "136"
It all went really cool after here (I placed the 7 in row3 next).
Super cool.
What a gorgeous puzzle!
26:44 finish. Everything's coming up 9s! I was wondering if it would wind up two sets of each digit 1-8 in the corners, but couldn't prove it. Glad to see that it worked out that way!
Nice song at the end as well!
At 27:15 you can make progress with the 11 sum in r7c7/r8c7/r9c7. Ask whether a 1 can be in those three cells - it can't, as all three see 6, 7 , 8, and 9, and thus you can't make 10 from the remaining two cells. This puts a 1 in box 9's 18 cage, whose remaining digits must add to 14. As there's a 9 in the box already, we see that the 18 cage is made up of 1368, putting 245 in the original r7c7/r8c7/r9c7 cells.
27:17 Simon just said that the triplet in column 7, box 9 adds up to 11, so C7R4 and C7R5 are a domino with 8 total, so must be a 1/7 pair, and C7R4 cannot be 1 because it puts an 8 on the arrow which is forbidden by the antiking constraint, so must be the 7 etc.
[edit] 30:07 So, Simon got the 7 in C7R4 with much more beautiful logic than just column scanning. I love that man.
Very much appreciate your performance at the end :)
I've finished this one in 28:08 ! First time I've beaten the video length by so much!
Simon, is it the case that the orthogonal arrows from the centre need to be the mirror images of the diagonal ones? It is the case in this puzzle but it's hard to prove that it has to be the case.
wonderful outro, Simon! [I jumped to the end to listen to it first]
Rules: 2:16
Let’s get cracking: 4:00
I may have overcomplicated this a little in my solve. I took some time to prove to myself that the red cells could not have any repeated digits in them (as that would lead to the repeated digits being "seen" along all four edges of the Phistomophel ring, where they would clash with the givens). I also spent a fair bit of time and effort trying to find a way to prove that the 18 cages had to have two pairs of digits that each summed to 9 (which I failed to do, but which turned out to be true in the end). My final time was a nice, round 50:00
Tip for the software: If you have a pencil mark in a bunch of places you want to get rid of without deleting the contents completely (this works for center or corner marks), highlight the cells or everything and hit the number. It will fill in the squares that don't have it, then hit the number AGAIN, and it will remove it from all cells. It works like "fill all, then erase all."
What a lovely outro Simon!
one thing that could work all around the grid, is when you placed 6 on box 6, @26:44, you asked than how much left for reach 45. and you've the answer, 11. than you could have done math in column 7, giving you a 7-1 pair right up to the 6. and that would have gave to you the remaining 3 digit in that column. since this puzzle is simmetric, i think you could have done the same all around the ring
I wish I'd seen how the cage totals force the arrow totals, but here's something I was pretty proud of spotting about the diagonals: the 3s and 7s have sort of an x-wing-ish behavior that gives us some digits.
On the "forward slash" diagonal, 7s are restricted to r2c2 and r3c3. On the "backslash" diagonal, 7s are restricted to r8c2 and r3c7. Between the two diagonals, we know that there will be a 7 in either r3c3 or r3c7. Because of the arrows those possible 7s are on, we know that there must be a 2 in either r4c4 or r4c6. Therefore, because of the king's move restriction, we know that r3c5 cannot be 2. If r3c5 can't be 2, then r4c5 can't be 7, giving us a 7 at r5c6 and a 2 at r5c7.
By the same logic, the possible 3s in r3c7 and r7c7 wind up giving us a 3 in r5c4 and a 6 in r5c3.
Second Aad's puzzle that I was able to solve. Woo-hoo!
Spotted the Phistomefel ring, got the 9s, made some other deductions, but got stuck, so now I'm finishing the video.
Absolutely amazing puzzle! Number 9 Number 9
Reminds me of the cover of Raventale's album Planetarium!
Quote of the day: "sorry, got interrupted there by my garage ringing to tell me my car has exploded again, so you have to excuse me when I cry silently"
Or: "we talk about Sudoku miracles all the time but what we just saw there was a true miracle where you press an F-key of some sort and it really does nearly break you"
Alright but I could feel the goosebumps when I heard the outro, it's like I could taste bobbins tea from my water bottle
Sheer class from Aad. He always sets such elegantly constructed puzzles.
Rather than use the diagonals to place the 9s, it was easier to note that none of the cages could contain a 9 due to Phistomefel''s ring, and each 9 in a circle removed two of the three options in each corner box.
After solving it very similarly to Simon, and in a similar time, I thought I'd try an experiment. I started again, placed the 9s, then filled all the remaining cells with 1-8. I then went through the puzzle, eliminating digits from wherever they were blocked by one rule or another. Then, using the remaining digits on each end of the arrows, I was able to make more eliminations. This left triples and quads all over the place, allowing further eliminations. The cages typically had only five or six different digits, so maths could work out which to eliminate. After that, it was just a quick mopping up. It took just over 20 minutes, so it was significantly quicker, but it did feel like I'd cheapened the puzzle and left me feeling a bit dirty.
I don't see it mentioned yet, but F5 refreshes the browser window. And as an extra, Ctrl + F5 will reload the page while updating the cache (or ignoring the cache depending on how you want to look at it)
Simon, are you taking song requests? :D It's one of the rare instances I slow the play speed to Normal.
@23:48. Goes to great lengths explaining the ring. Casually drops a 3 in R3C7 without mentioning king's move restrictions. I'm slow without my coffee :( took a little bit to figure out his logic.
I like that there is two ways to rule out the 9s at the 16 min mark. Since there cannot be a 9 in the ring there cannot be any in the cages either .)
About 70 minutes for me. I was really slow making progress on this one, at first due to misreading the king's move rile as a Knight's move and getting very confused, and then by trying to do later steps of the solve early. Really good puzzle, especially if you weren't being a doofus like me throughout the solve.
16:00 moreover, you know there are no 9s in the Phistomophel ring, so no 9s in the green boxes, which help place 9s in the corner boxes.
26:34 The squawk of despair
You should make a few videos about the techniques (The ring here, X-wings, etc), that way you wouldn't need to explain everything every time. Just put these videos in a playlist and link the playlist in the description.
I think there are videos like that in a playlist...? Probably older videos though
@@richy77 I quickly went over the playlists on the channel and couldn't find something like that.
42:24 for my solve. I did it a quite different way. After having spotted the logic with Phisomefel's ring, I just colored every cell in the central box and solved the colored sudoku. Maybe less efficient but very fun to do and not difficult at all.
Saw the Phisto ring right away, but had a slow start appreciably breaking in, but it moves fast after breaking in.
After you figure out all the nines, the bottom right 18 box has an 8 inside, so the rest add up to 10. But in the box they are already has 7,8,9 so the 10 sum always have a 3, and it should be on the ninth row. From that is quite straight forward
Would it be worth doing a separate video on the Phistomefel ring, and linking to it when required? Just to save you the time explaining it every time, and so that people who have been watching since the early days don't have to keep hearing it?
I looked at the puzzle and found that in the middle cell there had to be a 7 and a 9. I concluded that the puzzle was impossible, still went back to the rules and realized that there is a kings move constraint and not a knight's move.
I didn't watch the whole video, but it does NOT require the phistomefel ring to solve (or bifurcation). Straight solve in 30:55, with no special techniques. Very cool puzzle.
I took a rather different (albeit much uglier) path; I got the 9s the same, then worked out where 3 and 7 went in the central box by reference to the diagonals (as certain positions would have ruled them out of one diagonal or the other) then worked out that each of the corner cages had to have a pair of digits adding to 9 meaning they had to be two pairs of digits each adding to 9, which I was then able to use to unroll the ring (by virtue of knowing certain digits had to not be on one side of the ring) then work out the rest of the puzzle from there.
Yeahhh - Thank you for the setter video