Thursday 29 June 2023

Printable Sudoku Puzzles on the Live Sudoku Site

If you look at my Copyright Information page, you will see that I allow anybody to print, copy and distribute my puzzles free of charge. However, there is only ever one puzzle per post so your printing costs might make this uneconomical.

If this applies to you, take a look at the Free Printable Sudoku page on the Live Sudoku site. This lets you download PDFs which contain easy, medium, hard or evil puzzles, with either 4 or 6 puzzles on each page. You are then free to print and copy them as often as you wish. The page has other options too, including the ability to create blank sudoku grids.

I downloaded one of their books of evil puzzles, which contained 60 sudokus. I checked the grade of the first grid on SudokuWiki.org. This gave it a rating of Tough / 177. The solve path used naked pairs, naked triples, pointing pairs and a Y-wing. You can see the puzzle below if you would like to try it yourself:

Thursday 22 June 2023

Chess Solution no 11

 
15. ...  Nxd5
16. Nxd5  Qe5

Black's queen is simultaneously attacking the rook at a1 and the knight at d5. White must lose the knight to save the rook. In the actual game, white resigned at this point.

Chess Puzzle no 11

This position is from Dzhuguryan v. Rudzinska, Poland, 2022. It is black to play. What should she do?

See answer

Thursday 8 June 2023

Chess Solution no 10


35. ...  Bxf3+!
at which point white resigned in the actual game.
 
Here is the full solution to the puzzle I set:
 
35. ...  Bxf3+!
36. Kf1  Be2#
 
or
 
35. ... Bxf3+!
36. Ng4  Rxg4+
37. Kf1  Be2#
 
or
 
35. ...  Bxf3+!
36. Ng4  Rxg4+
37. Kh2  Bf2
38. Kh3  Rh4#

Chess Puzzle no 10

This position is from Wafa v. Navrotescu, Women's Olympiad, Chennai, India, 2022. Black to play and checkmate in 4 moves:


See answer

Solution to Sudoku no 705

Sudoku no 705 (Diabolical)

Sudoku grader and solver

See answer

Saturday 3 June 2023

Chess Solution no 8b

34. Nxe7+!

at which point black resigned.

The game might have continued as follows:

34. ...  Kf8
35. Qxh7  Kxe7
36. Qxg7+ etc.

or

34. ...  Kh8
35. Qxh7+  Kxh7
36. Rh1+  Rh2
37. Rxh2# 

Chess Puzzle no 8b

This position, which is continued from chess solution no 8a, is from Radusinovic v. Rajkovoc, Serbia, 2022. Black has just played
33. ...  Qh7? How should white respond?
 

Chess Solution no 8a

 
33. ...  Bf8
 
But see chess puzzle no 8b
 

 

Chess Puzzle no 8a

This position is from Radusinovic v. Rajkovoc, Serbia, 2022. Black (to move) has a strong position but is threatened with 34. Qxg7#. What should he play?


See answer