The New Sudoku Players' Forum

[m_b_metcalf]

Variants seem to have disappeared from the radar, but I found this X-samurai in my files, and thought it might be of interest. (Remember, each of the two diagonals in all five sub-puzzles also has each of the nine digits 1 to 9. This puzzle starts with all diagonal cells empty.)

Code: Select all

 . . 9 1 . 5 3 . .       . . 1 2 . 5 6 . .
 . . . 2 . 3 . . .       . . . 1 . 8 . . .
 5 . . . . . . . 4       5 . . . . . . . 7
 . . 2 . . . 6 . .       . . 2 . . . 3 . .
 . 1 6 . . . 5 8 .       . 4 6 . . . 5 8 .
 . . 8 . . . 7 . .       . . 8 . . . 1 . .
 2 . . . . . . . . 1 . 5 . . . . . . . . 6
 . . . 3 . . . . . 4 . 2 . . . . . 7 . . .
 . . 3 4 . . . . . . . . . . . . . 6 7 . .
             . . 1 . . . 3 . .
             . 6 . . . . . 9 .
             . . 2 . . . 5 . .
 . . 5 2 . . . . . . . . . . . . . 6 3 . .
 . . . 1 . . . . . 8 . 7 . . . . . 8 . . .
 3 . . . . . . . . 5 . 1 . . . . . . . . 1
 . . 3 . . . 4 . .       . . 1 . . . 5 . .
 . 1 2 . . . 9 6 .       . 4 9 . . . 6 8 .
 . . 9 . . . 8 . .       . . 8 . . . 9 . .
 9 . . . . . . . 2       2 . . . . . . . 6
 . . . 4 . 8 . . .       . . . 2 . 4 . . .
 . . 8 6 . 5 7 . .       . . 6 9 . 7 8 . .  [Edit 20.9.07: make more interesting]


Regards,

Mike Metcalf

[udosuk]

Thanks for the puzzle.

Just think you guys might like to know that every Tuesday DJApe's site releases a free Samurai Sudoku X puzzle on the following page:

http://www.djape.net/sudoku/wp/index.php/samurai-sudoku

Also, there is another one every 7 weeks from the affiliated site of the one above, Sudoku-Samurai.com, available from this page:

http://www.sudoku-samurai.com/samurai/index.php/samurai-x

[m_b_metcalf]

Regression testing of old code yields (very hard):

Code: Select all

 . . . 1 . 5 3 . . . . . . . 1 2 . 5 . . .
 . . . . 7 . . . . . . . . . . . 7 . . . .
 . . . . . . . . . . . . . . . . . . . . .
 . . 2 . 5 . 6 . . . . . . . 2 . 5 . 3 . .
 . 1 . 7 . 4 . 8 . . . . . 4 . 7 . 3 . 8 .
 3 . 8 . 1 . . . . . . . . . . . 4 . 1 . 9
 . . . . . . . . . 1 . 5 . . . . . . . . .
 . . . . 2 . . . . . 8 . . . . . 2 . . . .
 . . . 4 . 7 . . . . . . . . . 3 . 6 . . .
 . . . . . . . . 1 . . . 3 . . . . . . . .
 . . . . . . . 6 . . . . . 9 . . . . . . .
 . . . . . . . . 2 . . . 5 . . . . . . . .
 . . . 2 . 4 . . . . . . . . . 1 . 6 . . .
 . . . . 8 . . . . . 2 . . . . . 2 . . . .
 . . . . . . . . . 5 . 1 . . . . . . . . .
 6 . 3 . 1 . . . . . . . . . . . 4 . 5 . 3
 . 1 . 5 . 3 . 6 . . . . . 4 . 7 . 3 . 8 .
 . . 9 . 6 . 8 . . . . . . . 8 . 5 . 9 ..
 . . . . . . . . . . . . . . . . . . . . .
 . . . . 2 . . . . . . . . . . . 6 . . . .
 . . . 6 . 5 7 . . . . . . . 6 9 . 7 . . .


Code: Select all

...1.53......7...............2.5.6...1.7.4.8.3.8.1.................2.......4.7...
..12.5.......7...............2.5.3...4.7.3.8.....4.1.9.............2.......3.6...
...1.5.......8...............1...3...6.....9...2...5...............2.......5.1...
...2.4.......8.............6.3.1.....1.5.3.6...9.6.8...............2.......6.57..   
...1.6.......2.................4.5.3.4.7.3.8...8.5.9...............6......69.7...


Regards,

Mike Metcalf

[enxio27]

Mike, did you generate this somehow? If so, do you have a program to generate other Samurai (and possibly other gattai)?

[m_b_metcalf]

Mike, did you generate this somehow? If so, do you have a program to generate other Samurai (and possibly other gattai)?

Yes, I have a program that generates Samurai, with an X option. It's only semi-automatic, however. Interest seems to have dropped to zero.

I'd be happy to generate a puzzle on request.

Regards,

Mike Metcalf

[enxio27]

Yes, I have a program that generates Samurai, with an X option. It's only semi-automatic, however. Interest seems to have dropped to zero.

Well, not *quite* zero, but it sure does seem that I'm the only one left who is interested in gattai puzzles rather than killers and searching for the "hardest" sudokus.

I'd be happy to generate a puzzle on request.

That would be lovely! The limit of my technique repertoire is currently at X-wings, naked triples/quads, etc., but I'm working on swordfish, as well.

Also, Richard Broughton (Sudoku Solver, http://www.rcbroughton.co.uk/sudoku/ss_index.htm) is valiantly attempting to make a gattai generator (mostly for my benefit, I guess), but he has run into a few snags. If you would be willing to advise him, we would both very much appreciate it.

[m_b_metcalf]

I'd be happy to generate a puzzle on request.

That would be lovely! The limit of my technique repertoire is currently at X-wings, naked triples/quads, etc., but I'm working on swordfish, as well.

Also, Richard Broughton (Sudoku Solver, http://www.rcbroughton.co.uk/sudoku/ss_index.htm) is valiantly attempting to make a gattai generator (mostly for my benefit, I guess), but he has run into a few snags. If you would be willing to advise him, we would both very much appreciate it.

The puzzle below is not too difficult. I hope you enjoy it. There are three levels of coupling in samurai:

none: the five individual puzzles can each be solved without reference to one another;

weak: at least one puzzle can be solved only by sharing solved clues with a neighbouring puzzle;

strong: at least one puzzle can be solved only by sharing pencil marks with a neighbouring puzzle.

This puzzle has strong coupling. It's in three different formats.

Richard Broughton can contact me by PM and I'd be happpy to help, if I can.

Have fun,

Mike Metcalf

Code: Select all

 . . . . 3 . . 8 . . . . . 7 . . 2 . . . .
 . . 8 6 . 1 5 . 9 . . . 2 . 9 3 . 1 5 . .
 . . . . 7 . . 6 . . . . . 6 . . 7 . . . .
 . 9 . . . . . 5 . . . . . 4 . . . . . 5 .
 2 . 5 . . . 9 . 7 . . . 8 . 5 . . . 4 . 7
 . 6 . . . . . . . . . . . . . . . . . 8 .
 . 5 . . 8 . . . . . . . . . . . 9 . . 4 . 
 6 . 2 3 . . . . . 2 . 6 . . . . . 4 7 . 5
 . 3 . . 5 . . . . . . . . . . . 5 . . 1 .
 . . . . . . . 8 . . . . . 3 . . . . . . .
 . . . . . . . . . . . . . . . . . . . . .
 . . . . . . . 2 . . . . . 4 . . . . . . .
 . 5 . . 9 . . . . . 5 . . . . . 9 . . 3 . 
 9 . 3 7 . . . . . 7 . 8 . . . . . 2 7 . 5
 . 6 . . 5 . . . . . . . . . . . 8 . . 4 . 
 . 4 . . . . . . . . . . . . . . . . . 7 .
 8 . 2 . . . 4 . 5 . . . 1 . 7 . . . 5 . 8
 . 7 . . . . . 8 . . . . . 4 . . . . . 1 .
 . . . . 3 . . 4 . . . . . 7 . . 3 . . . .            X-samurai, fairly easy
 . . 8 9 . 4 5 . 2 . . . 4 . 1 9 . 5 8 . .
 . . . . 2 . . 1 . . . . . 9 . . 7 . . . .

Code: Select all

000030080008601509000070060090000050205000907060000000050080000602300000030050000
070020000209301500060070000040000050805000407000000080000090040000004705000050010
000000000000206000000000000080000030000000000020000040000050000000708000000000000
050090000903700000060050000040000000802000405070000080000030040008904502000020010
000090030000002705000080040000000070107000508040000010070030000401905800090070000

[enxio27]

The puzzle below is not too difficult. I hope you enjoy it.

Thank you very much! I will give it a try!

There are three levels of coupling in samurai:

none: the five individual puzzles can each be solved without reference to one another;

weak: at least one puzzle can be solved only by sharing solved clues with a neighbouring puzzle;

strong: at least one puzzle can be solved only by sharing pencil marks with a neighbouring puzzle.

Very interesting! Thank you for this explanation!

Richard Broughton can contact me by PM and I'd be happpy to help, if I can.

Thank you! I will let him know.

[enxio27]

Just FYI--I'm still working on this puzzle. I've been busier than a one-armed paper-hanger since before (U.S.) Thanksgiving, but I'm hoping that things will ease up for me timewise after the first of the year. I've made one pass through each of the grids so far.

[enxio27]

Finally had the time to sit down with this puzzle and finish it off. Great puzzle! Thank you so much for sharing!

You're right, it's fairly easy. I think the most advanced technique I encountered was an X-wing or two. Still very enjoyable, though!

[m_b_metcalf]

Finally had the time to sit down with this puzzle and finish it off. Great puzzle! Thank you so much for sharing!

You're very welcome!

Mike