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

https://www.sudokuwiki.org/Escargot

https://sudokuspoiler.com/sudoku/9
My original solver…
1 6 2 | 8 5 7 | 4 9 3 
5 3 4 | 1 2 9 | 6 7 8 
7 8 9 | 6 4 3 | 5 2 1 
---------------------
4 7 5 | 3 1 2 | 9 8 6 
9 1 3 | 5 8 6 | 7 4 2 
6 2 8 | 7 9 4 | 1 3 5 
---------------------
3 5 6 | 4 7 8 | 2 1 9 
2 4 1 | 9 3 5 | 8 6 7 
8 9 7 | 2 6 1 | 3 5 4 

1 6 2 ║ 8 5 7 ║ 4 9 3 
5 3 4 ║ 1 2 9 ║ 6 7 8 
7 8 9 ║ 6 4 3 ║ 5 2 1 
══════╬═══════╬══════
4 7 5 ║ 3 1 2 ║ 9 8 6 
9 1 3 ║ 5 8 6 ║ 7 4 2 
6 2 8 ║ 7 9 4 ║ 1 3 5 
══════╬═══════╬══════
3 5 6 ║ 4 7 8 ║ 2 1 9 
2 4 1 ║ 9 3 5 ║ 8 6 7 
8 9 7 ║ 2 6 1 ║ 3 5 4 

With only naked singles, grid23. With hidden singles, grid20.