The New Sudoku Players' Forum

[Mathimagics]

Returning to the subject of disjoint 2CT's, I have been searching your b134679 pattern (12 x 2CT) with various configurations of 12 disjoint 2CT's in b258, thus giving a total of 24 x 2CT's.

So far I have found only case where reduction testing allowed 4 x 2CT's to be removed, and so my best result is currently 20 x 2CT .

[Mathimagics]

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I have found a puzzle with 19 disjoint 2CT's:

[mith]

I got it down to 3 solutions, but not making any good progress on modifying it from here.

We do now have several examples with a pair of 9CTs plus one 2CT. For example: https://f-puzzles.com/?id=258rmyq5 (remove the r8c5 bulb for the 3 solution 19 cell)

Played with the 19c again today, and found another 3 solution (along with 4-8). I'm not quite at the point of coding this search, but if the next time I do this doesn't make progress it may be time.