05/10/17 tough puzzle from sudoku.com.au

This one is equivalent to 05/09/28. Proof :

1) Take 05/09/28 grid.

2) Now move rows 123456789 (1=bottom!) on new positions 213456798

3) Now move columns abcdefghi(a=left!) on new positions higdefcab. Do you begin to feel like déjà vu?

4) All that's left now is to rename last grid's values 123456789 on 749681325 and you get exactly 05/10/17's puzzle.

Here is the dictionary which takes you from former puzzle to today's.

1) Renumber as shown below :
1->7,2->4,3->9,4->6,5->8,6->1,7->3,8->2,9->5
2) Replace cells as shown below.

Now applying the same "dictionary" (changing rows, columns, values) to proof of 05/09/28 you will mechanically get a proof of today's. E.g. first filled cell in 09/28 was "h2=8%block". It becomes "a1=2%block". Try it ! Or see the method explained step by step on 10/08 example.

See more illustrated examples of equivalence between puzzles : 09/26,09/29, 10/02, 10/03, 10/04.

In case that you be lazy enough not to find it by yourself, here are hints for today's proof (automatically derived from 09/28's proof).

1) easy eliminations to 26 filled.
2) considering 7 in Bb2, 4 in Bb2, 9 in Be5, 37 in d7d9, remove some possibles : that will get to 39 filled.
3) considering 35 in g1g2, remove some possibles : will get to 54 filled.
4) Look at two possibles 4 in Ci, conclude that a7=4 anyway. Now to unique solution.

back to sandbox