Hello!

I am trying to get through on this "deadly" Killer Sudoku, published recently in the Times with the solving time listed as 55 minutes.

Any suggestions on a good solving technique from this point?

Thanks!

14 posts
• Page **1** of **1**

Hello!

I am trying to get through on this "deadly" Killer Sudoku, published recently in the Times with the solving time listed as 55 minutes.

Any suggestions on a good solving technique from this point?

Thanks!

I am trying to get through on this "deadly" Killer Sudoku, published recently in the Times with the solving time listed as 55 minutes.

Any suggestions on a good solving technique from this point?

Thanks!

- Super Sudoku
**Posts:**9**Joined:**19 November 2005

If it's any consolation (which it probably isn't) you got further than I did. It was the first Times Killer for ages that I hadn't been able to do within the time limit. I just hit a wall.

I look forward to someone showing us the light...

I look forward to someone showing us the light...

- SPARTAN-117
**Posts:**6**Joined:**08 July 2006

Having second thoughts after I posted. I suppose this is not an ordinary 9x9 Sudoku, what with all the blue bubbles and little numbers in the image in the first post. I'm guessing that the little numbers are the sum of the values in the bubbles. If that is true then I have no idea if it is a valid puzzle. Sorry for the confusion.

Tracy

Tracy

- TKiel
**Posts:**209**Joined:**05 January 2006

I printed the puzzle off again and I think I've finally cracked it.

The 19 on the top row (R1) must be 3+4+5+7 because obviously the 3 is a 1+2. Therefore R1C4 and R1C9 are a pair - one is a 6, the other an 8.

Now, this means that R2C8 is either a 3 or a 5.

R2C1 & R2C2 must equal 13. This can now be 6+7 or 5+8.

IF we put in 5 and 8, R2C8 must be a 3, which would make R1C9 an 8 and R1C4 a 6. There is now no possible location for a 6 in R2. Therefore R2C1 and R2C2 are actually 6 and 7.

From here, the rest of the puzzle seemed OK. Definitely the hardest Deadly Killer for a couple of months.

The 19 on the top row (R1) must be 3+4+5+7 because obviously the 3 is a 1+2. Therefore R1C4 and R1C9 are a pair - one is a 6, the other an 8.

Now, this means that R2C8 is either a 3 or a 5.

R2C1 & R2C2 must equal 13. This can now be 6+7 or 5+8.

IF we put in 5 and 8, R2C8 must be a 3, which would make R1C9 an 8 and R1C4 a 6. There is now no possible location for a 6 in R2. Therefore R2C1 and R2C2 are actually 6 and 7.

From here, the rest of the puzzle seemed OK. Definitely the hardest Deadly Killer for a couple of months.

- SPARTAN-117
**Posts:**6**Joined:**08 July 2006

Thanks for your replies here. This one was probably harder than normal as it fell on a bank holiday weekend. I wish the solving times reflected the difficulty of the puzzles more closely. I feel they are scared of mentioning anything beyond the 1 hour mark.

- Super Sudoku
**Posts:**9**Joined:**19 November 2005

TKiel wrote:Simple Sudoku says this puzzle has too many solutions to count, so don't waste your time trying to solve it.

Tracy

As this is a killer sudoku rather than a convensional one there are more rules that apply and therefore it cant be solved using sudoku rules alone.

It probably does only have one solution

- Pi
**Posts:**389**Joined:**27 May 2005

This puzzle does have a unique solution and it's rated IQ by Perfect Sudoku, so it can be solved by using deduction logic alone.

From the position you have given, it is rated BRAIN. You need to apply cage splitting.

For example, look at rows 8 and 9. You should figure out that R8C1+R8C2+R8C3=17. From there after some elimination you should figure out that R8C5+R8C6=16 (9+7). Therefore, R7C6=6 (naked single).

From there no more cage splitting is required, you just need to play with cage sums and standard sudoku techniques.

From the position you have given, it is rated BRAIN. You need to apply cage splitting.

For example, look at rows 8 and 9. You should figure out that R8C1+R8C2+R8C3=17. From there after some elimination you should figure out that R8C5+R8C6=16 (9+7). Therefore, R7C6=6 (naked single).

From there no more cage splitting is required, you just need to play with cage sums and standard sudoku techniques.

- djape
**Posts:**34**Joined:**27 September 2005

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