The New Sudoku Players' Forum

[urhegyi]

Here the specific placement of the JS blocks forces the normal sudoku blocks, so you can add the windoku and diagonal blocks to make a JSWBX.
Easy example:

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#1/WX/B4,JSB
...4.2...8.......1..2...9............8.....7............8...3..1.......6...2.9...
122211333122211444122211444555666444555666333777666333777889998777889998555889998

Analyze log:

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Eliminated candidates per Method and per Sudoku

Method   \  Sudoku |   SER |     1
                   |-------|------
Not counted elims  |     0 |   125
Naked Singles      |   0.1 |    35
Hidden Singles     |   0.2 |   108
Naked Single   [1] |   2.5 |     9
Naked Pair     [2] |     3 |    13
Naked Triple   [3] |   3.6 |     8
Naked Quad     [4] |     5 |    11
Hidden Quad    [5] |   5.4 |    16
Hidden Triple  [6] |     4 |     8
Hidden Pair    [7] |   3.4 |     1
                   |-------|------
Eliminated Cand's  |   334 |   334
Sum(SER * Cand's)  | 292.2 | 292.2

Initial Candidates :   334
Maximum SER rating :   5.4 <- Approach
Labour rating      : 292.2 <- Experimental rating
Time needed        : 00:00:00.832
SiSeSuSo Solver and Generator (version 2021-04b)

Filling an empty grid with 9 clues (example row 1) isn't enough to have a unique solution. What will be the minimal number of clues to have a unique solution?

[Hajime]

Filling an empty grid with 9 clues (example row 1) isn't enough to have a unique solution. What will be the minimal number of clues to have a unique solution?

By hand and T&E:

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#1/WX/B4,JSB
123456789...............................6..............................27........
122211333122211444122211444555666444555666333777666333777889998777889998555889998


12 givens, but not minimal. The 2,6,7,9 from row 1 can be eliminated. So 8 clues.

[urhegyi]

I was still investigating if there were other configurations possible for JSBWX till I found thisone:

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#1/WX/B4,JSB
....8.................6....157...694.........296...738....9.................1....
336666777366666777344444777344411222341111152333115552888555552888999992888999922

or an even harder one:

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#1/WX/B4,JSB
.....................1.4....5.....9....976....9.....3....2.8.....................
336666777366666777344444777344411222341111152333115552888555552888999992888999922

First example pointing/claiming + subsets + singles
Second example contains also turbotfish.
Third example like second one but also with generalized intersection:

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#1/WX/B4,JSB
....8........2......9...3..............9.6..............5...4......4........1....
336666777366666777344444777344411222341111152333115552888555552888999992888999922