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This interesting Classic Sudoku (6x6) puzzle can be solved in three steps.
(puzzle found with Sukaku 6x6Explainer)
After basics, the configuration is as follows.
,-----------------------------------,
6 | 2 *16 3 | 156 15 4 |
5 |*16 4 5 | 2 3 *16 |
|----------------+------------------|
4 | 1456 2 146 | 1456 145 3 |
3 | 3 *(5)16 146 | 1456 1245 *(2)16 |
|----------------+------------------|
2 | 14 3 2 | 14 6 5 |
1 | 1456 156 146 | 3 124 12 |
'-----------------------------------'
a b c d e f
As usual, many ways are possible.
The strong link (5)b3=(2)f3 is nice
(internal guardians of the bivalued oddagon *(16))
and leads to placements: +5 b3, +5 a1 (how ?)
Move 2 is a simple skyscraper and move 3 is similar (same idea) to move 1.
I propose the following 6x6 Classic Sudoku puzzle.
(puzzle found with Sukaku 6x6Explainer)
After no basics, the configuration is as follows.
+----------------+----------------+
| 26 3 24 | 2456 2456 1 | 6
| 5 126 124 | 3 246 46 | 5
+----------------+----------------+
| 23 25 6 | 45 1 345 | 4
| 13 4 15 | 56 356 2 | 3
+----------------+----------------+
| 126 1256 3 | 2456 2456 456 | 2
| 4 256 25 | 1 2356 356 | 1
+----------------+----------------+
a b c d e f
Update (March 18, 2025)
+----------------+----------------+
| 26 3 24 | 2456 2456 1 | 6
| 5 126 124 | 3 246 46 | 5
+----------------+----------------+
| 23 25 6 | 45 1 345 | 4
| 13 4 15 | 56 356 2 | 3
+----------------+----------------+
| 16-2 1256 3 | 2456 2456 456 | 2
| 4 256 25 | 1 2356 356 | 1
+----------------+----------------+
a b c d e f
For step 1: (2)a2 is easily shown to be false, using (1)a2=(1)a3.
For step 2: there is an almost turbot fish on 6 using cells f2,f5,b5,a6
that eliminates (6)a2, solving the puzzle.
I expected to solve the following puzzle very quickly,
but only after some effort a path was found in three steps.
(generated and displayed with Sudoku6Explainer)
After performing basic moves:
+-------------------+-------------------+
| 4 156 3 | 125 16 26 | 6
| 156 2 16 | 135 1346 346 | 5
+-------------------+-------------------+
| 26 46 5 | 23 34 1 | 4
| 3 14 124 | 6 5 24 | 3
+-------------------+-------------------+
| 156 13456 146 | 13 2 36 | 2
| 126 136 126 | 4 136 5 | 1
+-------------------+-------------------+
a b c d e f Classic Sudoku
(Update: Sept 30, 2025)
+-------------------+-------------------+
| 4 156 3 | 125 16 26 | 6
| 156 2 16 | 135 1346 346 | 5
+-------------------+-------------------+
| 26 46 5 | 23 34 1 | 4
| 3 14 124 | 6 5 24 | 3
+-------------------+-------------------+
| 156 13456 146 | 13 2 36 | 2
| 126 136 126 | 4 16-3 5 | 1
+-------------------+-------------------+
a b c d e f Classic Sudoku
I could not find a one-stepper for this one.
My first step was a M-wing that removes (3)e1.
Update (Oct 2, 2025)
+----------------+----------------+
| 4 156 3 | 125 1-6 26 |
| 156 2 16 | 135 34 346 |
+----------------+----------------+
| 26 46 5 | 23 34 1 |
| 3 14 124 | 6 5 24 |
+----------------+----------------+
| 156 1456 146 | 13 2 36 |
| 126 3 126 | 4 16 5 |
+----------------+----------------+
a b c d e f Classic Sudoku
My second step is an almost Kite that
eliminates (6)e6, nearly finishing the puzzle:
Update (Oct 3, 2025)
+----------------+----------------+
| 4 *156 3 | 125 1-6 [26]. |
| 156 2 16 | 135 34 346| |
+----------------+--------------^-+
| 26 [46]--5----|-23->[4]3 1 | |
| 3 14 124 | 6 5 [24] |
+----------------+----------------+
| 156 *1456 146 | 13 2 *36 |
| 126 3 126 | 4 *16 5 |
+----------------+----------------+
a b c d e f Classic Sudoku
So, for step 2, either we have a Kite(6) e1-f2-b2-b6, or
(6)b4->(4)e4->(2)f3->(6)f6
+--------------+-------------+
| 4 56 3 | 25 1 26 |
| 156 2 16 | 35 34 46 |
+--------------+-------------+
| 26 46 5 | 23 34 1 |
| 3 1 24 | 6 5 24 |
+--------------+-------------+
| 56 456 46 | 1 2 3 |
| 12 3 12 | 4 6 5 |
+--------------+-------------+
a b c d e f Classic Sudoku
For step 3, there are two easy ways to finish: Y-wing, or BUG+2.
This puzzle does not seem easy to solve very quickly.
I needed 4 steps, but perhaps with more analysis one can find a shortcut.
(generated and displayed with Sudoku6Explainer)
After performing basic moves:
+----------------+----------------+
| 35 4 125 | 126 123 136 | 6
| 6 23 12 | 124 5 134 | 5
+----------------+----------------+
| 1 23 246 | 2456 234 3456 | 4
| 34 5 246 | 1246 1234 1346 | 3
+----------------+----------------+
| 45 6 3 | 145 14 2 | 2
| 2 1 45 | 3 6 45 | 1
+----------------+----------------+
a b c d e f Classic Sudoku
Update (Oct 5, 2025)
+----------------+----------------+
| 35 4 125 | 126 123 136 | 6
| 6 23 12 | 124 5 13-4 | 5
+----------------+----------------+
| 1 23 246 | 2456 234 3456 | 4
| 34 5 246 | 1246 1234 16-34| 3
+----------------+----------------+
| 45 6 3 | 145 14 2 | 2
| 2 1 45 | 3 6 45 | 1
+----------------+----------------+
a b c d e f Classic Sudoku
My initial step eliminates (4)f3 [single digit pattern].
My second move eliminates (3)f3 and (4)f5 with a chain
with 4 strong links.
+----------------+----------------+
| 35 4 125 | 126 12 136 | 6
| 6 23 12 | 4 5 13 | 5
+----------------+----------------+
| 1 23 246 | 5-26 234 45 | 4
| 34 5 246 | 126 1234 16 | 3
+----------------+----------------+
| 45 6 3 | 15 14 2 | 2
| 2 1 45 | 3 6 45 | 1
+----------------+----------------+
a b c d e f Classic Sudoku
My third step removes (2)d4 and my fourth removes (6)d4.
I could combine them in a single step, using a double kraken
to remove (5)c1.
EDIT: corrected last statement [on solution in 3 steps].