Thanks so much for this feature! Just want to mention that mirrored digits is a constraint that I've only seen from the inventor, christournet, so far. I highly recommend this to all the puzzle setters out there. It creates some unique bits of logic and even made me jump out of bed to start setting a puzzle once (this one).
Today a video from a Simon 4 years younger than this one popped up ("The most under-used sudoku technique") and it was so nice to see their beginnings and how much the channel has evolved: * from solving standard sudoku to the weirdest rulesets this side of the Milky Way * from basic SudokuPad features to "3-In-The-Corner Effect" settings * from sound quality with "room for improvement" to phenomenal ASMR quality * from great Mark and Simon to even greater Mark and Simon creating a fantastic community around them
I say this with love, Simon not smiling and sort of monotone to always smiling if not with his mouth then with his voice and eyes! Always one of the highlights of my day
It really is cool to see Simon and Mark make logical deductions in a breeze after you remember the first puzzle they ever saw that ruleset or technique on.
I remember using old version of their app, pretty standard back then. But suddenly this guy name Sven came up with SudokuPad, everytime I solve Sudoku in their app I had a huge improvement in my skills. Also the coloring, that is the best feature in my opinion. Like, never have I thought about coloring a Sudoku grid, not in a decade I've played Sudoku.
Watching Simon, I feel like a kid on his first bicycle, being given a gentle push and going WHEEEEE once I have learned to balance. I needed a little nudge to get started and then it was smooth and delightful the whole way around.
18:20 Simon, I love the way that you pause and ask us to have a go at the logic before you explain. It’s what makes you an amazing teacher and has taught me so much about sudoku over the last year or so.
I enjoyed the daily videos each and every day, with all the amazing sets of puzzles nowadays. This is one of my favourites, the beautiful yet simple ruleset, and very smooth and well-thought solve path by gdc and Simon. 50 minutes just flew past.
I loved how you figured out that 5 had to be the mirror digit in box 5 which allowed 9 to still be the line total. There were several other moments when you pointed something out (which digits could not be on the lines fully contained in boxes 4 and 6, for example) which were brilliant and eye opening for me. Thanks for this wonderful video!
I feel like out brains work opposite one another. Around 19:30, you spoke about your deductive reasoning of box 6 and why a 1 had to be on the small zipper segment. My brain told me "since there is a natural 8 in the center and the adjusted digit has already been used in the box, 4 cannot be on the 8 zipper since it will not have a mate"
Simon you was a lucky guy in this puzzle. In minute 26:13 you put a 9 without know where is the mirror cell, so the 9 could be on the zipper line and match with a 7 :D I love see you solving puzzles. Thanks for create this amazing videos ;)
The first thing I noticed in this puzzle is you can immediately place the 9 in box 4 by noticing every cell in rows 3, 4, and 5 is a blobble or a line. Only one 9 can be mirrored, so at least two real 9’s exist in these rows, which have to be on the blobbles. The blobble in r6c3 is set up such that its value must be even, so you can’t put a 9 there, and so row 6 can’t have a real 9, using up the mirrored 9, which means the one place in row 4 that can have a real 9, r4c3, must be a real 9.
Simon : You can use adjusted 8 and natural 2 Me : which 2 sudoku numbers can sum up to 2? I like how Simon can get so confused by the new rules his brain just can't follow and does silly mistakes
A puzzle that felt simultaneously semi-approachable and mind bending. Finished in the about the same time as Simon, but so glad I could double check my deductions using the video as I went along, as the mirroring made me wonder if I’d missed a ‘gotcha’. Also weirdly felt like a fog of war without the fog as the first half required focussing on only a very small zone of the puzzle at a time.
20:15 finish. It took me a minute to get started, mainly because it didn't click that 5 mirrors to 5. Once I got over that hurdle, things fell into place for me. Such a fun puzzle, excellent!
28:59 This was a very fun puzzle to solve! Puzzles like this are the exact right difficulty for me. Complex enough that it's interesting and I feel proud of myself for seeing the logic, but easy enough that I don't get stuck and stare at the grid for minutes at a time.
Even before using the "secret", you can know 9 is in the central cell. If it weren't, it would need to be mirrored, and have a value of 1. But that would mean two 1s on the line, and both would need the same partner, which is impossible. So, 9 is in the centre. Then, all the other digits pair off to make 9, so the only way that will work is if the mirrored cell is 5, so that the pairing isn't broken. Same logic works in box 6. Since 9 is on the line, it must be mirrored, and have a value of 1. So, the real 1 _can't_ be on that line, and instead must be on the big central 'Z' line. Basically, wherever the line sees itself, you can't duplicate values, so if you have a mirrored value, you _can't_ have it's real counterpart. (Exception: If the real and fake values are themselves partners.)
A struggle that nearly destroyed me at multiple points (I kept mixing up which cells paired on some of the zippers), but a beautiful one that came together in the end. There's also another way to get Row 2. If 9 is at the end, because of a "secret" technique, the sum of the remaining values is 21 = 45-9-2-7-6, and the line has to be a multiple of 3, which would force 7 to be the middle digit, which it can't be.
@11:00 Another way to logic the break-in in box 5 is to ask what happens if 9 isn't in the center. All the digits are on the zipper here, so the mirrored 9 (1) and 1 would both be on the lines, and both would need the same digit X to add up to X+1 in the middle. So 9 simply cannot be mirrored as box 5's line is laid out. The same logic follows after for the real mirrored digit. There are 8 digits which pair off into 4 ways of making 9. But if you mirror anything except 5, you cause the same problem of digits not adding up properly.
It took me about 220 minutes to complete. I made a mistake in box 1 and I didn't notice it until I was working on box 2 and 3 while I had boxes 4, 5 ,6, 7 and 9 done. I had to watch the video to see where my mistake was. In box 1 for making up nine, you have 2 and 7, I had 4 and 5. After finding that it was mostly smooth sailing. Fun puzzle!
31:45 can someone explain to me why he remove the 8 under the 2? just because the 2 is worth 8 on the zipper line doesn't mean it should push actual 8 around
Some crazy logic in this one. I had a lot of fun figuring it out! My time today was 43:48, and I was solver number 997. (If only I'd taken a minute or two longer, I might've been number 1000!)
Interesting, my idea for the break-in was actually a bit different, and didn't use the secret, though it gets you to the same place. I thought about boxes 5 and 6, and that normally, if no funny business were going on, then the single bulb in those boxes would be the only places that could contain a 9. But those bulbs share row 5, so one of those boxes has a 9 not on the bulb, which must therefore be mirrored. If you try to put the mirrored 9 on the line in box 5 though, you get the problem Simon points out early on, that you'd have two cells valued 1, and they'd both need the same partner in the box. This really was fun to solve. It flowed really smoothly, feels like it would be an excellent choice to introduce someone to these 'adjusted digits' styles of puzzle. Other than occasionally forgetting that the mirrored digits is the one across from 5 and not 4.5 (for some reason I kept thinking about mirrored 3 being 6 and vice versa) everything seemed smooth and approachable for a puzzle of its difficulty rating. I do feel slightly bad for all the natural digits that seemed to be kicked off their lines by the adjusted ones though lol.
Alternative start: I did box 7 first, because the blobble HAD to be even and at least 6. 6 can't have four pairs so the blobble center outside box 7 was 8. First I realized that mirroring does NOT change parity, and a single mirror does NOT change the number of possible pairs in a single box. In box 4 the zipper center MUST be ODD (because an even blobble must use an even number of odd digits), and 7 does not have four different pairs. As ALL digits (besides the center) are included in zipper-pairs, the blobble is an unmirrored 9. Now all pairs add up to 9, and therefore the only possible mirror is 5. With 9 on the zipperline in box 6 it is mirrored, and it is obvious, that the unmirrored 1 in box 6 had to be on the zipperline from box 5. Thus its 9-pair 8 had to be in box 4, where I already had the 8 in the blobble outside box 7, such that I needed a mirrored 2 😊. The rest of the puzzle was relatively easy (because I was able to solve it 😄), although box 2 and 3 took me a long time.
Had to peek at the video to be reminded of the nine rule with zippers lmao, but after that I solved it in 43:49 which I am quite happy with. Very fun puzzle once I got going.
Simon could have worked out the lines in box 5 in the beginning. The two dots couldn't be 2,8 with 2 being the value of the dots, because it would need two 1s on the lines, which is impossible. So the dots are 4,6 or 3,7. Then there are two 4s looking into box 9, so the 4 in box 9 needs to be on the lines/dots. If the dots are 3,7 you need 3 and 4 on the lines to add to 7, and the 3 is already used. So the dots have to be 4,6. I'm sure this is how it was planned to be done bc it's much more elegant than the way Simon used.
24:09 You can prove here that it's going to be a natural 4 because if it's a modified 6 you then have to make three (natural) pairs of different digits summing to 8 with 2+6 off the table.
26:04 - wasn't this an error that ended up being lucky? I wonder if that ended up making the solve easier? Or am I missing something lol... Simon said 9 can't go on the zipper line, but it absolutely could have been a mirrored 9, which would have been 1 on the zipper line. Edit: oh shoot... I missed the fact that 1-9 can only be mirrored once... dang it! that's where I got stuck too lol
21:40 Simon, I watch a lot of your solves, and am very happy to follow you into realms of numeracy that I’d be lost in otherwise. I lost the plot of this one back in box 6, and I was okay with accepting your analysis as correct. But at this point in the video, you mentioned “a blobbled seven” like it was a common feature of sudoku puzzles, and it made me question my reality. Can you (or any other kind soul) tell me why the 7 is blobbled here? Is that even the correct past-tense term? I have never heard of blobble digits before now. Does that mean unaltered, or green, or is it some other arcane property of sudoku that is more closely-guarded than The Secret? I thought I was one of your closest friends, since you’ve told me The Secret a thousand times! I don’t know what to think anymore… (Only joking, but I really would like to know what a blobbled digit is.)
Me at 43:43 : okay I still don't get the whole ruleset, natural, naughty, sums, mods, opposite stuff but it's fun to watch the cracking. Me 6 minutes later: omg you finally ruled out the normal sudoku rule "6" in the 6th block of the middle square, damn you 666 beast.
Rules: 04:16 Let's Get Cracking: 06:29 Simon's time: 44m14s Puzzle Solved: 50:43 What about this video's Top Tier Simarkisms?! The Secret: 8x (07:22, 09:09, 09:18, 09:32, 09:42, 09:42, 09:51, 41:07) Three In the Corner: 1x (46:16) And how about this video's Simarkisms?! Naughty: 27x (20:26, 20:43, 20:52, 21:12, 21:14, 23:08, 25:28, 34:23, 43:59, 44:44, 44:47, 44:50, 44:52, 44:58, 46:31, 46:36, 46:40, 47:16, 47:39, 48:06, 48:29, 48:34, 48:36, 48:36, 48:53, 48:59, 49:13) Beautiful: 10x (16:13, 16:16, 16:25, 16:33, 16:43, 16:46, 20:31, 30:28, 33:32, 51:10) Ah: 7x (12:01, 20:20, 24:41, 24:43, 30:28, 35:24, 39:10) Brilliant: 6x (00:51, 02:36, 31:00, 31:04, 50:34, 50:58) Hang On: 6x (16:31, 38:47, 38:47, 38:47, 38:47, 46:10) Clever: 5x (19:14, 19:40, 19:40, 20:29, 45:52) In Fact: 5x (11:42, 20:35, 40:58, 48:29, 48:42) Sorry: 4x (07:44, 15:37, 26:00, 49:30) By Sudoku: 4x (26:14, 32:14, 43:00, 46:29) Obviously: 4x (07:44, 08:23, 38:17, 39:24) Cake!: 4x (02:31, 02:32, 02:38, 03:39) Goodness: 2x (35:46, 49:37) What Does This Mean?: 2x (12:37, 35:04) Nonsense: 1x (37:35) Break the Puzzle: 1x (34:37) Incredible: 1x (01:35) Gorgeous: 1x (45:31) Hypothecate: 1x (31:23) Shouting: 1x (03:59) We Can Do Better Than That: 1x (46:10) Pencil Mark/mark: 1x (34:25) Triangular Number: 1x (13:26) Most popular number(>9), digit and colour this video: Forty Five (6 mentions) Nine (90 mentions) Green (10 mentions) Antithesis Battles: Even (5) - Odd (0) Higher (5) - Lower (1) Highest (2) - Lowest (0) Row (13) - Column (10) FAQ: Q1: You missed something! A1: That could very well be the case! Human speech can be hard to understand for computers like me! Point out the ones that I missed and maybe I'll learn! Q2: Can you do this for another channel? A2: I've been thinking about that and wrote some code to make that possible. Let me know which channel you think would be a good fit!
Great puzzle! I had to restart 2 times, my problem with zipper lines is that I seem get them confused with arrow sums. So in box 7 I was thinking how do I make 4 digits on each line add to something less than ten, by having a naughty digit enabling a repeated 1 or 2 of course! Then I liked that awful logic so much that I couldn’t see anything else. Of course that doesn’t work either but I still couldn’t shake the bad assumption. I did get there in the end once I realised that it was just completely wrong.
18:20 Why can't those two cells be 23? Once 9 is used as 1, nothing combines with the actual 1 to get whatever they sum to. 1 must be in one of those cells. 4 must be the other, because 4+4 = 8 can't go on that zipper line. 24:00 Block 5's mirrored digit must be in row 4, and is 5. That finishes the triples. 38:10 What bad things happen if R2C6 is 8?
Did it in 53:10. It would have been fun if the mirrored 7 (value 3) appeared in a corner when the real 3 didn't, or if the mirrored 3 (value 7) appeared in the corner. Would either of those warrant a song?
Thanks, but as the value of the mirrored 5 is 10 then the cells would have to sum to 10 if the mirrored 5 is n the centre. Am I missing something obvious?
The rules mention “values an equal distance to the circled center,” but Simon seems to interpret this as “cells as equal distance to…” This rule set isn’t clicking for me.
25:31 "A 147, (a snoooker maximum), Simon says. Personally, i say "snooker" (like booker). Simon, do you say "boooker?" (As in "Please pass me that 'boook' in the library?".? That would sound silly, wouldn't it?! To each his own, though. Just funny. 😂
English (in most dialects, anyway) has a short double-o sound, as in look, book, hook, and a long double-o sound, as in room, boom, gloom, and, yes, snooker. It's not silly, it's just the way the language works!
@@rentalcustard No, it's not how "language works," it's how "colloquilisms (or regional things) works." I said "to each his own." I happened to see a British person say to me:"There is no 'right' tenant, so why is there a 'left' tenant?" (This British person had a problem with "leftenant" in other words) I think the topic of conversation was "van Gogh." ("van Go" versus "van goff"), a Dutch person said (of which Vincent van Gogh was from): "It's actually "van gök" or something. The "topic of conversation being "van Go" now, he was happy to leave behind "left tenant" because there was no "right tenant." So yes, it's about how "local colloquilisms/languages work," but it's more on "how colloquilisms work." Thanks for the input of "broom and gloom" and such though. I said "to each his own.."
@@rentalcustard It's not even "regional colloquilisms," I bet this came up with only "Snooker" players. (An even more closed group) They probably joked: "We say 'gloom, broom and spook', so why not 'snooker' like 'snooper' or 'scooper'?" Yeah, like a "pooper scooper, lol. (A "pooper scooper" is a real thing over here -- I think it's a cat litter "scooper" or a dog poop "scooper"). Yeah, that's where ya can take "snoooker." ;) 😉 😂
Because there is only 1 mirrored digit in each column, row, and box the center has to be 9, and the mirrored digit in it is 5 because the entire middle box is on the zipper. Different logic same answer.
I got the update for the new puzzles on the CTC app. I was able to solve it.........almost. I get down to maybe 8-10 digits and it requires me to violate the anti-knight's rule. The solution is wrong. I solved the puzzle ignoring the solution and found that only about 6 digits need to be changed as a result of that. But the solution in the app breaks the anit-knight rule on 9's. The 2nd puzzle is perfectly fine.
49:59 with a couple of looks at the video when I messed up. For some reason, when doing digits that sum to 9, I kept thinking that the mirrored digit would be 9-x, not 10-x (eg, 1 becomes 8 instead of 9).
It's too late in the evening for all that unnecessary maths! In box 5, if the 9 is not on the bobble, it has to be masquerading as a 1, in which case the 8 would be on the bobble, the 9as1 would pair with the 7, but what would we do with the real 1.... broken. Thus 9 is on the bobble and all possible 2 digit sums to 9 are needed, so the only mirrorable digit is 5. In box 6, the 9 cannot be in row 5, so is on zipper, so must be mirrored as a 1, so the real 1 cannot also be on the same zipper. Then the 8 has to bobble and the 2 mirrors to an 8 at the other end of the line to pair with the 1. 4 cannot go on the 8zip, so must pair with 5 on the 9zip.
It's easy to see the middle digit is 9 because if it was anywhere else in box 5 it would have to be the mirrored digit. That would give it a value of 1, but you would have to have a real 1 in the box too, and that would force you to put the same digit twice in box 5 opposite the 1 and the 9. So clearly the 9 can't be the mirrored digit, and it can't be a real 9 on the zipper line unless it's the center digit.
Why can't R5C9 be the mirror cell? Why can't 9 be unadjusted in box 6? 12:20 "9 unadjusted can't be on a zipper line because there's no way to make this ten or higher" You can make R5C9 ten or higher by making it a mirror cell
This was one of the better puzzles I've seen done on this channel. Seems like Simon was never truly stumped or led down any "bobbins" paths, as the logic was always clear on how to solve this. Even when the logic took a long time to work out, Simon always seemed like he was making positive progress towards the solution.
And what I like about Simon is that if he does figure something out in a relatively inelegant way, he makes the effort to go back and point out the easier way to make progress, for example "a better question is to ask where does the 1 go in box 6" or some such. He's not so fixated on solving the puzzle quickly that he fails to explain the best solution.
Simon: you CAN reduce the blobble pair in box nine to 3, 4, 6 or 7: otherwise you would either need a natural ONE on a blobble, which is impossible, or a natural TWO, which would need two natural 1s in the same box, which is also impossible.
r7c3 tripped me up because I didn't realize that it was doubled for the zipper, instead I thought it simply equaled the center and thus used a mirror digit... turns out that doesn't work! Glad I spotted my error though and was able to still solve the puzzle
I think that is what the rule actually says. There is only a single value 1 away and the sum of a single value is just that value. I hate it when there are incorrect or at best ambiguous rules given.
Another way to think about the break-in (which doesn't use the secret) is to say a digit other than 5 is the mirrored digit in the box, then to consider the digit with the same value as the adjusted value of the mirrored digit. It is clear that the other side of that digit would have to be the same digit as the other side of the mirrored digit, thus repeating a digit in the box. Ergo, only a digit that adjusts to itself can appear in that box and it must be 5. EDIT: This is essentially the logic used to find the 1-4 pair in box six applied to box 5.
C3 R7 messed me up a bit when I got through the logic of the first part but when I got through that cell having to be a double it was smooth sailing from there on. I love these types of puzzles where its a doubler or a mirror value or whatever.
Helped me to note immediately that the change in value is always even. Combined with the 3x zipper lines, it made it fairly easy to identify candidates. e.g. @40:43 Natural sum is 22: 3x7 = 21 would require an adjustment of 1....so can't happen.
I feel like this may be less rigorous than Simon, but I found it easier to figure that it must be five getting adjusted in the central box because I could see in a world without mirrored digits, it would have to be nine in the middle and pairs adding up to nine around it, because you have to have a sudoku digit in the middle that is capable of being added up to in four different ways, and nine is the only such digit (1-8,2-7,3-6,4-5), and then if you introduce mirroring, it breaks up your pairs because you can only have one mirrored digit, unless you have a mirrored digit that's not really a mirrored digit at all (i.e., 5).
You could do it in the same sort of way as other people mentioned in the comments regarding the nine in the central cell. If some digit is mirrored into some other digit, that would put a repeated digit on the zipper, once normal, once mirrored, so unless they both sum to nine which they can't since nine isn't divisible by two, then the partners of those digits would be a repeated normal digit so it would break sudoku.
i tried something more formal but still easy to grasp (well maybe it's just me). fact 1: the difference of 1&9, 2&8, etc is always even. fact 2: introducing a mirrored digit to a box/row/column changes its initial sum of 45 by 0, +-2, +-4, +-6, +-8. fact 3: the sum of the VALUES of box 5 has to be divisible by 5 due to the zipper line. result: 45 + value adjustment is divisible by 5 only when the adjustment equals to 0, therefore the mirrored digit in box 5 is the digit 5.
I got 65 minutes. Decent job, except I screwed up some logic and somehow switched in my mind the rules to be more like an arrow sudoku, where along the line towards the dot must add. I lost some good time there. Overall, very enjoyable!
Solved the puzzle and started the episode to see Simon's solve, only to see him talking about mod 5 division in the middle box right off the bat. Obviously he was right but that is NOT how I found the answer myself lol.
An easier deduction for box 6 is that if the 9 is transposed to 1, there cannot be another (actual) 1 on that line, or you'd have to repeat a digit on the zipper, which means 1 goes in r5c7/8 Edit: Oh nvm Simon figured it out a few minutes later haha
The easier way to get the central 9 is to realise that if it went on the line, it would have to be a 1, but then you'd have two 1s paired with different digits yet summing to the same value. It therefore had to be 9 in the centre with 18, 27, 36, and 45 values, and the only way to do that is by mirroring the 5 to itself. The 9 in box 6, which must be mirrored means that line can't have a second 1 on the line, so the real 1 must be on the Z, with either an 8, or a mirrored 2 on the opposite end. In box 7, there had to be a sum of 8, since the shared cell means it's even, and it has to have three other different ways to make it. This means there's a virtual 28 pair in box 4, and the 2 must be mirrored. I was sceptical when I started this, thinking it was just another setter trying to complicate an already interesting ruleset. However, it soon won me over. This was very interesting. The fact that the adjustments acted to either raise or lower the value added something to the puzzle that doublers don't.
@19:32 good morning, Simon! You indeed could never put two values of 1 on the lines, but once the blobble was deducted to be 8, you could neither put a 4 on the line.
11:30 - 9 has to go in the central cell. It's the only number out of all of them that can be summed to 4 different ways with digits 1-8. The number of zipper line cells outward from the central circle are 4 on both sides AND they are still inside the same Region. Which means you have no choice but to use all 4 combos of digits 1-8 to add up to 9: 1+8, 2+7, 3+6, and 4+5.
