Phistomefel's Archer 

I think it would’ve been quite amusing if Phistomefel had written his 5/10 rule as: “Digits separated by a V must add up to 5, and digits separated by an X must add up to 10. All V’s and X’s are given.”

When Simon is using terms like "real yellow" and "high purple", you really know we are swimming in deep waters.

Ah a 100 minute phistomephel video... Time to be late for work tomorrow

I love the fact that Simon's computer seems to participate in the hard work that solving a Phistomefel puzzle is.

I am once again making an appeal to Sven to add dark, medium, and light variants of all existing colors to help save Simon from himself.

Me: getting frustrated at Simon not seeing an obvious digit Also me: watching Simon in absolute awe because I stand no chance solving this puzzle

The Saga of The Solver and The Fly Simon attacked by fly 33:10 Return of the Jed-fly 34:49 Simon getting ticked off by fly 37:57 Dive bombing 38:56 Aagh! 40:09

1:26:52 - 1:31:52 That 1 In Box 7 was killing me with the 24 pair next to it.

This video has it all, difficult color choices, Simon choosing the extra route to certain deductions, yelling at the screen, flying disturbances, and, above all, another fantastic solve. Such a good watch!

I'm a setter. I've had a few puzzles featured on this channel (genuflect) and others. I love setting so much that it's fooled me into thinking that perhaps I'm halfway decent at it. I even had the conceit that maybe -- for all his obvious talent -- Phistomefel could somehow be matched if...well...if I ever get lucky, I suppose. I no longer think that (yes; it shouldn't have taken me so long to give up such a silly thought). He's truly some kind of genius, far above the mortal coil. (I know, I know; tell you something you DON'T know, right?)

44:20 I'm hereby calling on Phistomefel. Create a RU-vid channel and upload only a single video, which is just a recording of yourself laughing.

Imagine having guests over and saying you need to be alone in your room with a laptop for a quick “20 minutes adventure” and you come out over an hour and a half later, all sweaty and with the face of pure bliss… they’d be setting you up for an intervention in a heartbeat haha

Enjoy your hols Simon and have plenty of cake. You have no idea how much you all mean to us and we miss you as much as we miss you even if it is a plain old shout at Simon. Also the mental relief you give people cannot be stressed enough this channel helps me so much out of dark places please keep solving as you also help my soduko skills and keep me on the straight and level path

this community and channel are so wholesome, i started setting puzzles myself cause i was so inspired. I hope you‘ll keep doing this for a long time!

If you miss doing these videos while you are on holiday, you definitely made a good career move. Thanks for taking the time to do this one.

Sagitta is one of the Greek constellations, which was first catalogued by the Greek astronomer Ptolemy in the 2nd century. The ancient Greeks called Sagitta, Ὀϊστός (Oistos), meaning 'the arrow'. In geometry, the sagitta is the distance from the center of an arc to the center of its base. Like an arrow in a bow. So it is an appropriate name for this sudoku with arrows... :-)

1:11:20 We discovered that "5+purple=orange/red" in box5 so the arrow in box 6 cannot be "5+purple" otherwise the "orange/red" circle would clash with the "orange/red" cell above. So you must have the "89" cell on the arrow forcing the 8, the 9... and everything

Oooo. A new Phistomephel movie. Wow! Where did I leave my popcorn? Thanks to both you and Mark for continuing to do these daily video, Simon. I know that I really look forward to them every day. Fun fact, Warmaster Horus revered the constellation Sagitar and the Emperor referred to Horus as his Dreaded Sagitarry. I hope I remembered that right. Been a long time since I read the start of the Horus Heresy.

I just wanted to say that poor Mr Simon is being trolled by his laptop. Since there is no Maverick flybys every so often, the laptop has taken it upon itself to use its fan as a “Maverick flyby”

Rules: 04:43 Let's Get Cracking: 06:15 Simon's time: 1h31m52s Puzzle Solved: 1:38:07 What about this video's Top Tier Simarkisms?! Phistomefel: 7x (01:18, 04:06, 05:59, 20:02, 26:50, 53:18, 1:39:31) Bobbins: 2x (21:37, 36:41) Maverick: 2x (40:15, 40:21) And how about this video's Simarkisms?! Hang On: 35x (21:29, 21:29, 21:32, 21:50, 27:18, 28:44, 29:55, 30:09, 32:11, 32:54, 32:54, 32:54, 32:54, 35:04, 35:06, 35:09, 35:09, 43:45, 44:16, 45:34, 48:39, 48:51, 48:51, 56:53, 58:58, 59:51, 59:51, 59:51, 1:09:18, 1:09:26, 1:10:52, 1:11:17, 1:11:17, 1:11:17, 1:14:36) Ah: 35x (09:39, 13:58, 13:58, 18:32, 19:15, 20:00, 21:50, 27:59, 32:54, 34:49, 40:07, 42:43, 42:55, 45:37, 47:01, 50:55, 50:57, 55:35, 57:26, 57:51, 1:01:21, 1:04:32, 1:04:32, 1:05:40, 1:10:10, 1:16:29, 1:20:57, 1:23:26, 1:25:40, 1:26:19, 1:30:01, 1:32:10, 1:34:20, 1:36:50, 1:37:36, 1:37:56) By Sudoku: 19x (19:48, 20:42, 23:11, 23:14, 24:32, 24:34, 25:39, 32:42, 39:11, 45:05, 46:35, 52:17, 55:26, 55:29, 1:30:36, 1:30:57, 1:33:41, 1:36:13, 1:37:43) Naughty: 16x (29:14, 29:23, 29:29, 29:35, 29:48, 29:55, 29:58, 30:52, 55:11, 1:02:43, 1:18:11, 1:18:18, 1:22:14, 1:24:09, 1:25:08, 1:33:52) Obviously: 10x (05:25, 07:15, 15:03, 15:44, 36:06, 45:44, 1:01:12, 1:19:23, 1:20:09, 1:37:06) Goodness: 8x (43:07, 54:57, 56:33, 1:01:21, 1:24:20, 1:29:39, 1:33:59, 1:39:26) Clever: 7x (11:19, 16:02, 1:01:21, 1:12:59, 1:13:09, 1:39:29, 1:39:34) Lovely: 7x (19:38, 57:51, 57:51, 1:16:24, 1:16:55, 1:18:08, 1:21:34) Sorry: 6x (03:18, 10:24, 26:25, 1:03:58, 1:20:16, 1:22:34) Good Grief: 4x (1:26:33, 1:29:27, 1:36:04, 1:38:03) What on Earth: 4x (38:04, 58:26, 1:10:29, 1:15:56) Beautiful: 4x (15:56, 1:16:12, 1:19:11, 1:19:13) Bother: 3x (27:57, 1:11:29, 1:27:41) The Answer is: 3x (25:16, 41:31, 1:15:20) Nonsense: 3x (22:32, 1:08:29, 1:08:32) I Have no Clue: 3x (58:48, 1:31:30, 1:34:40) Ridiculous: 3x (05:46, 51:09, 1:18:16) Surely: 3x (33:09, 1:06:54, 1:37:56) In Fact: 3x (15:31, 1:28:52, 1:30:04) We Can Do Better Than That: 2x (1:25:17, 1:31:22) Chromatic: 2x (16:00, 1:38:43) Useless: 1x (1:33:17) Axiomatically: 1x (1:22:55) Fascinating: 1x (08:07) Extraordinary: 1x (03:28) Elegant: 1x (1:18:58) Going Mad: 1x (33:32) Deadly Pattern: 1x (1:37:55) Whoopsie: 1x (52:34) Plonk: 1x (24:44) Wow: 1x (1:36:37) Next Trick: 1x (50:06) What Does This Mean?: 1x (47:01) Thingy Thing: 1x (1:16:34) Most popular number(>9), digit and colour this video: Ten (33 mentions) One (151 mentions) Orange (85 mentions) Antithesis Battles: High (55) - Low (47) Even (6) - Odd (0) Row (17) - Column (2) 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!

I think Simon deserves another holiday after solving this!

I usually don't have time for the longer solves but when I see phistomophel in the title, I make time.

For pencil marking something similar to this in the future, you can always use the high/low colours that you have and add in letters to describe the pairs. i.e. A/B go together, C/D go together, etc. Then select a letter for 5 which doesn't go with any. That allows you to keep your colouring, allows you to put the letter in the corner signaling what that cell's description is, and allows you to scan easier since you tend to not scan colours as easily, so scanning for letters instead may make more sense. I really enjoyed watching this solve. I had hoped you looked at row 7 sooner. The arrow that goes into Box 9 is actually interesting. Specifically because that arrow cannot sum to 3 anymore after you know Orange/Purple add to 5 and that Green and Purple look at R7C8. As for Phistomefel's laugh... I imagine Phistomefel is Laplace's Demon, so there's always a stereotypical demonic laugh in my head: very deep and slightly distorted.

Just finished and boy oh boy oh boy. This was fun to watch! I love Phistomefel videos, and this had such a deceptively simple ruleset: arrow and XV sudoku with all possible XVs given. Thanks CtC for your dedication to giving us these daily doses of wholesome. I hope you have a nice rest of your vacation, Simon and that Maverick only bothers you during solves. :)

Oh My, an hour 40 minutes! Let's get the popcorn popping before settling in!

You're not the only one that enjoys these non-interacting interactions!

"WHIRRRR!" said the laptop fan at my chamber door.

Sometimes Phistomefel puzzles aren't my absolute favorite, but this one is just incredible!! I love how the arrows in the middle boxes were enough to fill them in and the logic layered so intricately

This channel is my safe space. Thank you Simon!

Always fun to get back to this channel and a watch a few more vids. Two video's a day for 3 years is award worthy dedication! Well done!

Sagitta is simply the Latin word for ‘arrow’, and the astrological sign name is just the word for an archer, Sagittarius

I truly enjoy using closed captions on all Cracking The Cryptic videos. Especially when the name Phistomefel comes up. The computerized translations are always hilarious. Thanks for another fun puzzle!

🍿time! Thank you Simon for videoing during your holiday! Hope you are having a wonderful relaxing time!

Cells separated by a V or a X sum to 5 or 10. All possible Vs and Xs are given. 😜

I'm relaxing on holiday...watching you 'possibly' relaxing on holiday! 😆 Thank you as always Simon 🙏

I think this was my first Phistomefel puzzle that I actually largely figured out on my own. I didn't colour my digits (just what turned out to be 1's, 2's and the three arrow circles) instead I focused on figuring out the 1 and 9 positions which gave me a head start. I finished a full 10 minutes ahead of Simon. I'm feeling proud. I've learned a lot from this channel because I used to not have a clue how to get through a Phistomefel puzzle. I kept watching the video to make sure I hadn't made a mistake in my solve. Great puzzle and the solve was still the same as mine just I did less colouring. Great job Simon!

I really appreciate that you were able to release a video while on vacation. Thanks for the hard work!

Talking about naughty digits for over 90 min. You have to fall in love with this wonderful channel and of course Simon and Mark!

I took a lot of pride in solving this..... my favourite puzzle so far. Loved the way boxes 4 to 6 were the main logic puzzle. Elegant!

I'd love to see the rule. X and V rules apply. All possible X's and V's are given!

I see phistomefel on the thumbnail, i see 100 min video length, well now sleep is gonna wait lol

My favorite of all your videos are the Phistomefel solves. The quality of the puzzles coupled with your skill and reactions to the logic keeps me interested, even for 100 minutes! Thanks!

I just looked at the time and my word!!!! I do LOVE these longer videos! They are my favorite

Thank you for sharing a part of your holiday with us, and bringing us such a gorgeous puzzle! Have a wonderful holiday

Feels like interaction to me as well. I guess for more people here, since this channel helps people in life, not only by being very enjoyable, interesting and inspiring, but by being personal I guess. So much respect for being here every day (and it's oké to sometimes pre-record stuff). I pretty much watched all of the video's (I've got some waiting because of my vacation last month) since just before the lock downs (is it 2,5 years now?). Huge thanks for the 2 of you!

Wherever I see a super long video I get really excited

1:03:37 for me. awesome solve. loved that it was not a chaos construction sudoku.

46:11 Adding the red flash makes it more confusing that just having them both be green. The fact that you have already pencilmarked them with 1234 and 6789 is all that is needed.

Much kudos for taking on Phistomefel whilst on holiday and on a straining laptop. Enough of a challenge at any time, but of course we know that as soon as a new one comes along you’re like the proverbial ‘rat up a drainpipe’ 😀

Happy you're taking a holiday and happy we've got a Phistomefel opus. Never imagined I'd be happy about both of those things at the same time.

So many of us noticed the prerecorded videos and hoped you were well. So glad to hear you’re on a well-deserved holiday.

welcome back to the channel for a while Simon! Enjoy the rest of your holiday :) I'm really looking forward to the 500000 subscribers app

Holy s**t! What a puzzle! Absolutely amazing. No way I could have solved this in my lifetime without help from Simon. Incredible setting. And incredible solving.

Gosh dang!!! What an incredible video!!!! Characteristically brutal yet beautiful (brutiful?) setting from Phistomefel, and geez that is so hard to solve, you pulled it off so well Simon, no way am I attempting this lol. Row 7 of this puzzle might be one of my favorite single rows or columns in any puzzle, what with the beautiful bouncings back and forth. Just stellar. Take bows, both of you, and enjoy your holiday Simon!!

1:15:00 there's an even more elegant step here that was available quite a bit earlier. In box 6, if you put five on the arrow, you know from box 5 that five plus purple equals orange-red, but that arrow's circle SEES orange-red. By placing the five, you then get green-red on the arrow and the middle three boxes collapse.

Here's my reason for some of the 4 circled cells in the middle being the same: If the 4 circles in the middle were different, they would sum to 30. That would make the 10 arrow cells in r4 and r5 sum to EXACTLY 30, which means they are EXACTLY the digits 1-2-3-4-5 TWICE. Yet, 5 cannot go on a 3-length arrow in this puzzle, so it has to go into box 5 two times. From there, the only two that CAN be the same are r5c6 and r4c8.

Thanks Simon. Found this channel randomly a year ago and eagerly look forward to watching them. Sometimes I can now spot where to go next 😂😂 thanks

I'm enjoying trying to do these puzzles alongside you. I try to do them myself without help but I'm not an expert yet; this one I definitely had to pause a few times to see what you were doing! Thanks for the help and good job.

41:02 for me. What a puzzle!! Incredible break-in, I loved it!

Loved it as usual. Brilliant Puzzle and great solve. What i found most difficult was how to pencilmark it. I used colours at first but then switched to letters and used big and small letters. That made it harder to see the restrictions in the circle in box 9. And then the finishing off was just good fun, almost like a reward for all the work before. This channel really never disappoints. Looking forward to celebrate the 500k with everyone :)

75 minutes into my own attempt, and I've got a handful of pencil marks and that's it. I've played through many bifurcation possibilities (as far as I could take them anyway) and found many cool tricks about how the logic of it works, which would be incredibly useful if I had any actual digits or even some pairs. But no such digits were forthcoming. So... off to the video to find out how the hell to even get started on this one!

So wonderful to have a "live" video today - as in, not prerecorded. Don't get me wrong, I am ENTIRELY in favor of holidays and pre-recording videos so that you truly don't have channel-duties. But I have missed you, too! (And in a way, maybe you would not have realized that you miss making videos if you had not had the experience of not making them...) And if there were a puzzle worth emerging in order to do, this was definitely it. To the solve: Simon, this was astounding. I did download the puzzle and take a look, for a lark, and came up with the challenge of the high-low pairings and the negative constraint, but of course I did that while popping my popcorn and getting my easy chair all set up for the duration. It turned out I had to go to bed in the middle, so I returned this morning, and I was at the point that you suddenly filled in the numbers across the middle three rows - amazing, Simon. I followed the logic all the way through, it all made sense, and maybe if I had enough time I could have actually solved this (or something like this - especially with your explanations of what you were thinking). I did not detect holiday brain; I did see a few digits that you could have noticed, but you were busy doing other more amazing things that noticing a 1 in row 7 forbidding a 4 next to it and such trivialities as that. Thank you for pre-recording so many videos so that your absence has been nearly transparent, and I look forward to your being home again and in the setting that I'm used to seeing you in. Have a great rest of your holidays.

We're well over a year in, and Simon still gets disproportionately excited about the fact the software permits him to put a 0 in the grid. Wonderful!

How to easily figure out the deduction that Simon made at 51:00 way earlier: Once you discover that three of the arrow circles in the middle 3 boxes have to be different, if you assume the fourth one (r5c6) is also different, they’ll add up to 30. Which means the arrow cells also have to add up to 30, so they have to be 1-2-3-4-5 in each rows 4 and 5. Which places 2 fives in box 5. So r5c6 has to be the same as r4c8.

Haha, Maverick is piloting this laptop, no doubt!

1:07:10 Don‘t know if anyone already wrote it in the comments, but I wanted to bring it up, because it‘s just brilliant. In the middle box, you can see, that 5+purple is red/orange, however in Box 6 we have an arrow with a purple on it, which cannot add to red/orange, since its circle sees a red/orange in box 6. That meens that the 5 must live in the bottom right corner in Box 6 and the purple is accompanied with the high green diget.

Stumbled upon this channel a year ago and what an amazing find this was.

WHEW! I was avoiding this puzzle because I was on the middle of an 8 puzzle streak of solving puzzles in under the video length. But I finally did it after my streak broke... and it turned out my solve was barely over the video length! 1:44:03 for my time!

Oh my this Phistomefel puzzle ! I'm looking forward to continue the watch of Simon struggling to defeat this beast ! I wanted to comment about the small trick I used when I was solving this puzzle , and It's that at min 26 you can prove that R5C6 and R4C8 need to be the same digit because of the number of low digits in box 5. What Simon missed is that you have 5 arrow cells in both rows 4 and 5 , and if they were the absolute minimum then they will sum up to 30 (15x2) and that won't work because you will need to have six cells in box 5 that are chosen from the digits 12345. The moment you know this information you can prove that R5C6=R4C8 because if it didn't your arrow cells will be forced to sum to 30 and the only way to balance the circles with the minimum of the arrow cells is to make them different digits (6789) and that breaks box 5 for the reason mentioned before. Great puzzle as always from Phistomefel but extremely difficult !

Simon's family: it's HOLIDAY Simon: This IS FUN

Great puzzle, great solve! Without watching the initial coloring in the middle rows I would never ever have been able to solve it. And it still took me more than two and a half hours without a fly annoying me big time :-) ! Big compliments to Phistomefel and Simon.

You don't know the joy I get in scrolling through my RU-vid feed, only to see that devil sitting there.

Took me about 2 hours 45 minutes, but was able to finish. This was actually the first puzzle I have attempted since discovering this channel about a week ago. :)

So I had a go at solving this one, got stuck for ages missing a medium difficulty arrow idea but after that I was rendered totally speechless (while also delighted to have finally found the main logic). That was simply a masterclass in algebra and geometry. Phistomefel how do you do it??! One word: UN-BE-LIEVABLE! :)

40:31 This came up on my feed earlier so I saved it to do tonight and then had the new Phistomefel drop so I got a double dose of delightfully dizzying devilishness. This was a pleasure from beginning to end. One of the my favourite puzzles I've attempted so far.

Hey Simon, do you have the ability to ask Sven to add/change something in his software? If yes then I might have some suggestions that would help with the coloring puzzles like this one: 1. Add a single pixel white outline around all the digits, this way they will still be visible on top of dark backgrounds, in fact that should make the digits visible on top of any background 2. Add a few more colors, eg. zero should be white, for uses similar to what you do with light gray. Maybe even add 9 more colors for more complex puzzles 3. Add a second pool of textured colors. I feel you quite often need to have complementary digits in those coloring puzzles, so maybe if you could do a yellow and textured yellow, it would be easier. 4. Swap Final Digit with pencil mark. Currently "ctrl" is the shortcut to do middle pencil marks, but there is no shortcut to do final digit. In reality, you are going to do a lot more pencil marking than final digiting, so its better to assume middle pencil mark is your "no button pressed" state, and ctrl should be the final digit.

1:18:30 "There we go! Done it!" Nice, I loved that moment.

You look exceptionally happy today. I can't wait to see the solve!

Had this puzzle open for almost a week and kept coming back to it as was determined to crack it, which I eventually did. Good to see Simon's magnificent solve though - his logic is so incisive that it makes me wonder how I didn't spot some of the things he did.

1:20:53 finish. One deduction that would have placed the 5 in box 6 a little earlier. If you look at r7c9, it has to be either high purple or high yellow. But in box 5 you already have a 5 plus low purple that equal high orange. Therefore, 5 can't go in r6c7. A brutally difficult puzzle, and a lot of fun!

Half way in and this already broke my brain about 75 times over. It also made me realize that one big reason for the increasing complexity in sudoku puzzles is just the superior note taking abilities that come with digital solvers like this one. No way anyone could solve this on paper, right?

Thanks for introducing me to this great puzzle. I found the breakin (deducing that the central square is 5) much easier to do using letters instead of colours. In case anybody is interested, here’s what I did. Choose letters A B C D for the low numbers and E F G H the corresponding 10’s complement of these low numbers . So according to the puzzle’s rules set, orthogonally adjacent cells with values AE, BF CG and DH are ‘forbidden pairs’. Without loss of generality, the top two rows of box 4 can be pencil marked as 5F/C/5E;A/H/B while G and D can be marked as appearing somewhere on the third row of this box. The central square of box 6 is then C or D, but since G, by sudoku, must either appear in the circle or in the middle row row of box 6 this rules out C, since CG is a ‘forbidden pair’. The top row of box 6 is pencil marked ABD/EFGH/ABD. D in the central square of box 6 then forces the arrow circle in box 6 to be G since the other values E, F and H give rise to ’forbidden pairs’ EA, FB or HD. The bottom row of box 5 can then be pencil marked EF/AB/AB. This in turn implies that C and G must be placed in the middle row of box 5. Since CG is a forbidden pair, C and G need to be separated by the central square of box 5. This central square is one of E, F or 5. It can’t be E or F since then the row 6 column 5 cell in box 5 , which is pencil marked as AB, would be orthogonal neighboured by both E and F again giving a forbidden pair. So the central square must be 5. After this, the puzzle becomes more or less normal!

Havent seen the entire video, but something Simon dosn't notice at the begining is that the 2 cell-arrow circles can never be 5 because then the arrow domino adds up to 5 and that's illegal.

132 minutes. What a treat to the brain. Thanks Simon and phistomafel

I’m loving holiday Simon

Love these videos, really enjoying them. I only found your channel recently and have been consuming them at an alarming pace. One thing I noticed that could have helped around 1:05 is that you did a great job of recognising which high and low digits couldn't go next to each other but there was an important corollary that would have saved time. If low yellow + low green = 5 and low yellow + high yellow = 10, wouldn't it always be true that low green and high yellow are 5 apart (with the same being true for the other pairs you found). You got there backwards by noticing that 3+8 would be too high for the relevant circle anyway but I thought this was an interesting wrinkle to notice.

I would miss the videos and mostly Simon a lot if this chanel would end one day :( Still one of the only things to help me fall asleep in just 10 minutes - not because it's boring, I try to watch as long as I can, but Simons voice is just really comforting and relaxing to me :) Thanks for the hard work!

What a puzzle. A fun one. Took me a while to solve it. Was a bit lost in the beginning for quite some time, but once I started using letters to notate different digits low and high digits, it got going slowly but steady. After middle 3 rows are solved, then it's a matter technique. I think, in these kind of puzzles letters are much more clear than colors. I am glad I didn't resort to bifurcation.

I couldn't have made all of Simon's deductions but the fact he hadn't noted so well what was high or low, or how many high/low in a given section (esp. in row 4) slowed him down where I sped along. But only on the force of his other deductions, which I had to refer to when I got stuck.

It's almost like the laptop fan is applauding you at key moments in the solve.

This channel is my current happy place.

Watching the video made me feel a bit better about my attempted solve. Simon got stuck for quite a while at the same place I did! I stared at it for so long but never figured out that R4 C2 and R5 C7 could not be the same digit. I like to try all the hard puzzles, but this one I had to come to the video to see what the next step was.

1:20:00 for the best moment in the video. 😆 I was even wondering for a moment what the problem / funny thing was. What a great puzzle and what a great solve. Both Phistomefel and Simon (and anyone who can solve this) are pure geniuses. And that's an understatement.

Please don't get me wrong, I really admire your skills and I'm myself are an amateur at best, but 1:09:45 I'm always astonished how you come to a simple conclusion, by the hardest route possible. That High-Yellow could never have been an 8 from the start, since it would force an 1 next to a 9. I hope, some day to ba able to get mildly competent at this and your videos are a huge inspiration and encouragement for me. Thanks for these wonderful hours of entertainment every day.

I know it’s been over a week since the solve video but I thought this may prove helpful. This sudoku may seem insanely hard but it is all about the approach. There are effectively 3 stages to the solve. Stage one is all about arrow geometry - Simon explains why the digits on the 3-cell arrows are from 1,2,3&4, he then attempts to solve using colouring. You have to start with the fact one arrow contains digits ABC and the other digits ABD, where A and B are the repeats (3 repeats breaks as Simon demonstrates) and work from there. I found it helpful to use letters and then colours once I had placed the letters to show pairs adding to 10 (ABCD being low, EFGH being high and then colouring A and E the same colour etc.). As long as you remember basic arrow maths (the 5 cells in 2 rows on arrows add to at least 31, so the circles cannot be different or they would add to 30) and apply the key deduction (that the digit in row 5 column 8 cannot be the same as the digit in row 4 column 2 for reasons that Simon explains, it took me a while to spot this), then the rest is just a case of placing letters and keeping pairs apart. Stage two relies on algebra. You should now have an arrow in box 5 with a 5 on it. In other words, some digit A equals a digit B plus 5. However, we know that A and its counterpart (which is not B as A and B are different colours) sum to 10, so replacing A with B+5, we get that (B+5)+C (the counterpart) =10 -> B+C=5. Therefore, B cannot go next to C and likewise the other 2 digits cannot go next to each other, meaning we can resume placing letters. The final part of this stage (besides simple eliminations such as 9 not being on an arrow and the removal of pairs of digits e.g. removing 4 from one red cell removes 6 from the other) is to note that the 2-cell arrow in box 6 cannot have a 5 on it, as it leads to a contradiction with the arrow we described in box 5 (if A=B+5, C cannot also equal B+5 as A and C are different i.e. it’s like saying that 6 and 7 both equal 1+5)!! This (and some basic eliminations) should allow you to determine all the digits and fully compete rows 4 to 6 of the sudoku. Stage three is to use the final clues and the negative constraint to finish the puzzle. Focus on where digits can go in row 7 and the restrictions on the arrows in boxes 7-9, using row 3 and boxes 1-3 to help. It may not always look straightforward but as long as you keep pairs of numbers adding to 5 and 10 apart, things should solve fairly smoothly from there. And that’s it! Definitely nowhere near easy but far from impossible to solve, if you stick with it. :)

🍿🍿🍿 Been looking forward to this! Very nice puzzle!

Most important part of this! Picking what colour to use

Phistomephel: let's make a puzzle so difficult to break-in with still such an ellegant and high brain power move that Simon has to take a holiday break from his holiday while being on holiday. Simon: *solves it in 100 minutes* Phistomephel: dang, that's not hard enough...

I would have no chance of solving this myself, so this was a nice watch. I will say, at the end (and perhaps long before that), when the colors have stopped being useful, I'm a proponent of clearing them instead of matching them. Once you know what number is associated with what color, the color stops being crucial. Clear it all for a nice, black-and-white board in the end.

This video is longer than a Movie and is more exciting than a Movie!