Making a Hard Sudoku really easy

Get three numbers into this Sudoku and you'll be flying along!

[SamuelEks]

When sudoku is the only place that you find naked singles...

[MotoCzar]

Him: *Took me a heck of a long time, almost 8 minutes*
Me: *(Takes a break 30mins in to look up sudoku tips)*

[davidh.]

One tip that I've picked up from watching these is to train yourself to occasionally scan the numbers in the rows and columns, looking for places where lots of different numbers overlap. Those are often places worth looking at more carefully.

R8C7 is a perfect example. If you scan the board you can see quickly that C7 has 2347, R8 has 3689, and 1 is in the box. So bam, you've just found a naked single 5.

Also look carefully at houses that have only a few empty cells, and make a note of what's missing from them. e.g. C5, which starts out with 5 digits given, leaving just 1238 to go. After checking the overlapping houses, while there are no singles out of the gate, you have already found two bi-value cells.

[YourCritic]

When Mark said pause, I spotted a naked 5 without even having to pencil anything in. Similar strategy to Mark's - I looked at cells with longest lines of intersecting digits and found that in box 9 the cell to the left of the 9 can only be a 5. Admittedly, that 5 placement doesn't seem to open up the puzzle much so eventually, the 2 on the third box would have been required.

[boorad]

Great tip — “sometimes you have to switch to cell thinking”. I often find these videos hard to follow because he goes so fast, but THIS was a truly brilliant tip. Thank you!!

[Do_not_assume]

Imagine telling your friends I'm off to play sudoku to look for naked singles...

[guus]

i literally solved a puzzle because of this video. Never actually did 'cel type thinking', thanks

[Utpalrai]

My highschool maths teacher gave us summer holiday work to solve Sudoku everyday from newspaper and paste it on a scrap book. From there I started solving Sudoku.

[yulana]

Just started sudoku 3 days ago with an app from boredom (and cause of memory issues), but the fastest I managed to solve an Expert puzzle (1 block with 6 empty cells and only around 1-3 numbers in blocks max) was 14 minutes, and ever since that 1 lucky time it takes minimum 22 minutes! my strategy of writing down every single possible number is definitely not working lmao. Definitely gonna check more of your videos out as I never thought of keeping it this plain, page wise!

[scholarcloudacademia]

He : I took hell a long time-8 minutes😔
Me : yeah I solved it in just 7 hours 😎

[zbkpruz]

OHHH I CAN SEE NOW WHY 2 WAS THERE

Look at the row and column where 2 was
5, 7, 3 was at the left so you cant place em anymore
6, 9 was at the bottom of it so you cant place these numbers too
4, 8 was at the box so you cant place em anymore

1 and 2 are the only choice left
1 is about to be placed there!
Making 2 the only number left!
Thx Cryptic

[Birchbayaromatics]

Very helpful method. IF you couple your method, while at the same time keeping an eye out for hidden pairs, it REALLY speeds up the process. I found several hidden pairs right away

[Chelovyek]

This has been one of the most helpful sudoku videos I have ever seen. Many thanks for your help! I don't understand why your ideas are not taught more generally. Hope you make many more videos.

[georgesthibaudeau]

I did this without notations. It took me a very long time: 38 minutes ! I found a naked 5 in box 9, at r8c7 and thopught there was some light at the end of the tunnel, but no such luck. Then I finally took a look at row 2 and found the naked 2. This was what was needed. Fun puzzle.

[SudokuSwami]

There is also a “Naked 5” in R8C7, on the very first move. :-))

[Abelhawk]

What do you do when you get bottlenecked and the only ones left are cells that can be one of two numbers?

[whocareswho]

I will say this one is a very nice example of the power of that 2 cells notation. Together with the scanning for cells that can only hold a single digit you have a real good puzzle for people just getting into sudokus and these two techniques.

[juhaloukaja]

Without the need for the ones in the top right box, bottom right box also has a naked single below the 7 in column 7, row 8. It's a 5. It sees 1, 7 and 9 in it's box, 2, 3 and 4 in the column and (3), 6 and 8 in the row so the only possibility is 5. I didn't spot the one Mark did in the top box, though.

[chrisbradley]

The first number i found was a 5 in row 8 column 7. If I identify a cell where a number cannot be I mark it with a dot in the appropriate spot, eg top left for a 1.

[Whatwhat]

Just a year later and the production quality has improved dramatically. I so wish this was solved through!