## 6x6 Killer puzzles - how hard can they be?

For fans of Killer Sudoku, Samurai Sudoku and other variants

### 6x6 Killer puzzles - how hard can they be?

How hard can 6x6 Killer puzzles be? As there are only 6 different numbers to be used, there are far fewer ways in which totals can be split up, so puzzles should be much easier.

How is this one for difficulty?

Code: Select all
`.. 09 | 18 18 | .. 08.. 09 | 18 12 | 12 08.. 18 | 18 12 | 12 ..------+-------+------.. 21 | 21 21 | 04 04.. .. | 21 .. | .. ..16 16 | 16 16 | 16 ..`

Key: 04 04 means a cage spanning 2 cells totaling 4.
It IS possible for a number to be repeated within a cage.
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Once upon a time I was a teenager who was active on here 2007-2011
999_Springs

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Joined: 27 January 2007
Location: In the toilet, flushing down springs, one by one.

### Re: 6x6 Killer puzzles - how hard can they be?

999_Springs wrote:How hard can 6x6 Killer puzzles be?

They can be very, very hard. And I'm glad that you ask this.

JC has made a couple very challenging ones in here:

http://www.djape.net/sudoku/forum/viewtopic.php?t=931

Notice that in those puzzles, numbers cannot repeat within a cage, as it's like the international standard of Killer Sudoku...
udosuk

Posts: 2698
Joined: 17 July 2005

Here is your puzzle in pic format:

And the solution is here.

Even with the awkwardness of having numbers repeating in cages, your puzzle isn't too hard at all... I'd say about 3-5 minutes of fun at most... JC's ones are much much harder if you like challenges...
udosuk

Posts: 2698
Joined: 17 July 2005

I forgot to say that I created the puzzle myself, so I don't need the solution...

udosuk wrote:
I'd say about 3-5 minutes of fun at most...

I gave this puzzle to three people a few months ago. (Their solving capability is that they can solve a Times Fiendish puzzle in 20-30 minutes.) Two of them thought that the 18-cage added up to 17 and ended up with a 4-cell unavoidable of 1 and 5 in r23c45 and even now they are still stuck on it. The third mucked up and finally completed it at the second attempt after 5 weeks. If you can solve it in 3-5 minutes I wonder how fast you can do a Times Fiendish puzzle...
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999_Springs

Posts: 367
Joined: 27 January 2007
Location: In the toilet, flushing down springs, one by one.

999_Springs wrote:If you can solve it in 3-5 minutes I wonder how fast you can do a Times Fiendish puzzle...

I haven't been doing the Killers from Times for a long long time... Before I leave them, I think on average they took me about 5 minutes without making pencilmarks and much less with...

If you're into challenging Killers, I suggest you visit these sites:

http://www.djape.net/sudoku/forum
http://www.djape.net/sudoku/wp
http://jcbonsai.free.fr/sudoku
http://www.killersudokuonline.com
http://www.sudocue.net

If you can do the more difficult puzzles posted in the above places I'm sure you won't be as surprised about anyone solving your puzzle in 3-5 minutes...
udosuk

Posts: 2698
Joined: 17 July 2005

Well, I'm into challenging small Killers.

Now I'm going even smaller...

How difficult can 4x4 Killers be!!? I can't find any of those on your websites.
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Once upon a time I was a teenager who was active on here 2007-2011
999_Springs

Posts: 367
Joined: 27 January 2007
Location: In the toilet, flushing down springs, one by one.

999_Springs wrote:How difficult can 4x4 Killers be!!? I can't find any of those on your websites.

Perhaps you haven't look hard enough...

Here is one, posted approx. one year ago...

Here is a 5x5 one, but it doesn't have "blocks", only rows & columns...

It's on the same page as the 2 evil 6x6 puzzles I told you about...
udosuk

Posts: 2698
Joined: 17 July 2005

The 4x4 puzzle was EXTREMELY easy. You just need to know what the values in a column and block add up to. Are there any harder ones?

The 5x5 puzzle: I was making good progress for ten minutes and then I put two 4s in both diagonals. Rats.
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Once upon a time I was a teenager who was active on here 2007-2011
999_Springs

Posts: 367
Joined: 27 January 2007
Location: In the toilet, flushing down springs, one by one.

999_Springs wrote:The 4x4 puzzle was EXTREMELY easy. You just need to know what the values in a column and block add up to. Are there any harder ones?

I don't think you can go hard at all with 4x4... After all with only 4 digits 1,2,3,4 there are only 6 possible pairs and 3 possible triples... How complicated can they get? Especially if you conform to the international standard rule of no repeating number in cages, you cannot have any cages larger than 4 cells... They're more for kids under 5... If anyone has trouble solving any 4x4 puzzles I'd suggest they stay away from any forms of Sudoku...

If you're looking for challenges, try the two 6x6 puzzles from my link above... Or are they too easy for you?
udosuk

Posts: 2698
Joined: 17 July 2005

### 6x6 Killer puzzles - how hard can they be?

I have posted
SuDoku 6 X 6 Grid Jigsaw Puzzles - 36 cells
@
http://www.easysurf.cc/sudoku6.htm
easysurf

Posts: 12
Joined: 14 June 2005

udosuk wrote:
They're more for kids under 5... If anyone has trouble solving any 4x4 puzzles I'd suggest they stay away from any forms of Sudoku...

I gave this puzzle to two of the three people that I had mentioned before:
Code: Select all
`6 5 5|56 6|6 5      -8 8 6 58 5 5|5`

(Each diagonal must contain the numbers 1-4 as well as each row, column and block. The lines show breaks between cages of the same number.)

One of these people solved the puzzle easily. The other one thought that 1+2+3+4=9 and wrote r2c3=5 and had to start again. He was much older than 5. Therefore I am not so sure about the truth of that statement.

I had another attempt at the 5x5. I put two 4s in row 4.

Then I had yet another attempt at it and eventually completed it. Next time I will NOT do Su-Dokus in ballpoint pen.
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Once upon a time I was a teenager who was active on here 2007-2011
999_Springs

Posts: 367
Joined: 27 January 2007
Location: In the toilet, flushing down springs, one by one.

999_Springs wrote:udosuk wrote:
They're more for kids under 5... If anyone has trouble solving any 4x4 puzzles I'd suggest they stay away from any forms of Sudoku...

I gave this puzzle to two of the three people that I had mentioned before:
Code: Select all
`6 5 5|56 6|6 5      -8 8 6 58 5 5|5`

(Each diagonal must contain the numbers 1-4 as well as each row, column and block. The lines show breaks between cages of the same number.)

One of these people solved the puzzle easily. The other one thought that 1+2+3+4=9 and wrote r2c3=5 and had to start again. He was much older than 5. Therefore I am not so sure about the truth of that statement.

I'll correct my statement to "they're more for kids under 5 or people with difficulty to sum up 1+2+3+4... If anyone has trouble solving any 4x4 Killer puzzles I'd suggest they stay away from any forms of Killer Sudoku (and Kakuro)...

For an average Killer Sudoku player, your puzzle can be solved well within half a minute in this sequence:

r1c23=[41] (b1)
r4c23=[23] (b3)
r23c3=[42] (b24)
r23c1=[24] (diagonals)
r23c4=[31] (r23,b24)
r14c4=[24] (b24)
r14c1=[31] (r14)
r23c2=[13] (r23)

udosuk

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Joined: 17 July 2005