A Sudoku With Only 9 Given Digits

*** Today's Sudoku ***

It's true you don't need to have 17 digits in a sudoku if the puzzle has some extra tricks up its sleeve. Today's puzzle comes from Sed Holaysan and it's called Number 5 Is Still Alive. This is a beautiful execution of a sudoku variant that appears in competitions from time to time. (And it IS quite approachable!) Play the puzzle at the link below:

Rules:
Normal sudoku rules apply. Digits in cages sum to a number that ends in 5. Digits cannot repeat within a cage.

▶ NEW PATREON CONTENT ◀

To all our patrons - thank you so much for your support.
We've just released The QAS ("Quite Approachable Sudoku") Hunt and Simon's solve of Phistomefel's Sequence Sudoku.

Also new on Patreon are:

- Solution videos for last month's Star Wars Sudoku Hunt by Peter C Hayward.
- Mark's solve of Phistomefel's Sequence Sudoku.
- Simon's solve of Fillomino Aquarium - the new beast of a puzzle by Phistomefel.
- Mark's latest solve of The Times Club Monthly Special crossword.
- the complete suite of solution videos (all 45 of them!!) to the Pyramid Puzzle Hunt.

You can join us on Patreon for as little as $2/month here:

▶ Contant Us ◀

Twitter: @Cracking The Cryptic

Our PO Box address:

Simon Anthony & Mark Goodliffe
Box 102
56 Gloucester Road
London
SW7 4UB

(Please note to use our real names rather than 'Cracking The Cryptic'.)

▶ SUDOKU PAD - Our New App ◀

It's OUT on Windows (released yesterday!) via Steam here:

You can now input your own classic sudoku puzzles into our software using our new App! The app also comes with 12 handmade puzzles from us and we're also releasing occasional bonus puzzles too. Already available on IOS and Android.

*** Our Book ***
The PDF is available as of today and the physical copy shouldn't be far behind. If you don't own the book then it can still be ordered here:

You can get the German language edition of the book here:

**************************************************************

▶ OUR ARROW SUDOKU APP IS OUT ON ALL PLATFORMS!
Here are the links:
Steam:
App Store:
Google Play:

▶ OUR KILLER SUDOKU APP IS OUT ON ALL PLATFORMS◀

▶ SIMON REACTION BOARD (!) ◀
With thanks to Andrea for creating this :)

▶ CTC FAN DISCORD SERVER◀

NEW: Guide To Our Discord Server:

▶ OUR BACK CATALOGUE – ALL CATEGORISED WITH LINKS!◀

▶ *NEW* CRACKING THE CRYPTIC MERCHANDISE◀

▶ OUR CHESS SUDOKU APP IS NOW OUT!◀

▶TRY OUR CLASSIC SUDOKU APP◀

▶TRY OUR SANDWICH SUDOKU APP◀

▶SEND US PUZZLES TO SOLVE/CONTACT US◀

▶FOLLOW US◀
Twitter: #crypticcracking
@crypticcracking

▶Logo Design◀
Melvyn Mainini

[sedsudoku]

Thanks for the great video solve, Simon! This featured pretty much every step I hoped would be found.

A very slight correction to 1:00, I'm not actually an author for the Sudoku GP, in fact I plan to participate this weekend. I just made this as a practice puzzle hoping to understand the variant better, as I've never tried it before. The path & visual theme turned out fairly interesting so I thought I'd submit it to the channel.

[Papierrazzi]

Simon, if I ever see you at a party you are in fact the person I'd like to talk to. If you bring Mark we can all stand in a corner to make it song worthy.

[HunterJE]

21:07 Classic Simon using cage totals to place the last digit in a row

[iabervon]

I think I managed to solve this puzzle without finding any deductions in the same order that Simon did. I liked that it had clever logic immediately available anywhere you looked, rather than making you search the grid for the one weak spot like puzzles with clever logic generally do.

[gcable]

I did it in 19:56, the closest I've ever come to Simon's time on a puzzle! I feel very proud of myself for this one.

[dubtak]

"Balance = Entropy" is an incredible puzzle and the rules will absolutely melt your brain. It is the best puzzle I've ever solved, bar none. I hope beyond hope that you solve it in a video.

[inspiringsand]

Rules: 03:40
Let's Get Cracking: 04:28
Simon's time: 18m22s
Puzzle Solved: 22:50

What about this video's Top Tier Simarkisms?!
The Secret: 2x (08:09, 08:12)

And how about this video's Simarkisms?!
By Sudoku: 13x (06:02, 10:35, 10:43, 14:19, 16:28, 16:51, 18:24, 20:22, 20:31, 21:36, 21:42, 21:47, 21:49)
Beautiful: 9x (05:43, 05:47, 10:08, 10:09, 16:03, 16:05, 19:04, 22:50, 23:23)
Ah: 4x (06:25, 11:43, 12:11, 13:53)
Naked Single: 2x (18:10, 19:44)
Stuck: 2x (06:14, 06:17)
Approachable: 2x (00:47, 22:58)
In Fact: 2x (05:09, 14:17)
Sorry: 1x (12:11)
The Answer is: 1x (15:20)
Clever: 1x (10:17)
Lovely: 1x (16:59)
Elegant: 1x (05:54)
Gorgeous: 1x (23:03)
Hang On: 1x (02:27)
Friend Fall Off a Roof: 1x (02:14)
Doesn't get a Song: 1x (21:34)
Obviously: 1x (08:12)
We Can Do Better Than That: 1x (13:39)

Most popular number(>9), digit and colour this video:
Twenty Five (9 mentions)
Two (45 mentions)
Red (8 mentions)

Antithesis Battles:
Even (3) - Odd (0)

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!

[stevieinselby]

21:00 Only Simon would start using maths to work out the 9th digit in the row when he's got the other 8 all written in 😂
A bit like spotting that the 5️⃣ in r9c9 ruled a cell out by cage before realising it ruled another cell out by column.

[thisphantonia]

During my solve I went an entirely different (and arguably way less efficient) route through the puzzle, but I stumbled upon some of the most beautiful logic I have ever discovered myself which Simon didn't.
I got the 2 and the 4 in r5r6c6 and then thought about r7r9c5 which I then realised were heavily restricted by the upper bound. They couldn't add up to 17 or 16 because of the 9 in their column; they couldn't add up to 15 because they couldn't be 6 and 9, and 7 and 8 would have made r4c6 a Schrödinger cell of 7 and 8; they couldn't add up to 14 or 13 because all of their options were ruled out by some givens, which made them a maximum of 12 with 4 and 8. But then, I noticed that in box 8, the U pentomino on the left added to 24 because 45 - 15 - 6 = 24, but in column 4 the four cells at the bottom added to 15 because of the 7 and 8 in their column as well as that cage. I then concluded that r6c4 had to be 9 less than r7r9c5 added together. Its minimum digit was 3 by the 1 and 2 in its row, while the maximum of r7r9c5 was 12, as I just explained. So I got equilibrium, and could enter all of that into the grid.

[steveoneill]

"Oh look! A 23 minute solve! Finally a puzzle I can try."
An hour into it with 1 box left to work and I hit a deadly pattern and an unsolvable cage.
So close.

[maritxuhh]

This is the first sudoku from your channel I've been able to finish on my own, thanks to everything I've learned watching your videos. Thanks for everything you do!!

[egghead]

First puzzle I've solved by myself without help so far. Finally getting the hang of them after a few months

[thenerdgamer]

I solved my first puzzle from this channel! Only took about 2h30min since I decided to ignore the 9-lenght cell strategy for a while and focus on the middle columns first. That was fun and I will try to improve :)

[stoosies]

I like seeing an easier but fun Sudoku on this channel. Sometimes the puzzles just melt my brain too much

[th.nd.r]

Absolutely beautiful and top quality setting and solving today. Love the long and difficult ones, but equally love the ones that give their beauty in simplicity. Well done Simon and Sed!

[monicaelena]

Life got in the way and I haven't watched your videos in about 2 months. Now coming back I see that your marking game has been stepped up, Mark is definitely very proud of you!

[Xiuhtec]

36:24 very fun, never felt stuck or frustrated, enjoyable for a novice like myself!

[zegres]

Balance = Entropy is an awesome sudoku and the rules are wordy but not too complicated.
Very excited to see it!

[slurpleslixie]

I missed most of the easy maths early on and instead treated it as a (really quite fun) colouring problem between boxes 1&4. Ignoring the entire rest of the grid and its deductions you can do quite a lot with just those two boxes and trying to figure out where the cells from one box must appear in the other box.

e.g. placing a 1/R4C1 pair into the R3C2-3 domino is fairly trivial, but it gives you a little information about where 2 can go, then trying to place the other cells that aren't in the 9-cell region from box 1 into the region in box 4 is some more fun colouring

[JustAGamerFan]

74:36 for my clear. It felt good to get back to the channel with a manageable sudoku such as this. Now to see you clear it thrice as fast as I!