Extra regions sudoku

For fans of Killer Sudoku, Samurai Sudoku and other variants

Re: Extra regions sudoku

Postby Hajime » Sat Jan 02, 2021 3:50 pm

urhegyi wrote:Your second grid is solvable on it's own even without generalized intersection. (string-kite/skyscraper/turbotcrane/x-chain[4]) Is this coïncidence or designed so?

Sometimes to solve a puzzle you can skip some methods and catch a candidate elimination in a next method.
You can uncheck and skip pointing/claiming and check generalized intersections method. It will find all pointing/claiming, because it is a subset of 2 houses of gen-intersection (2 or more houses).
All string-kite/skyscraper/turbotcrane/x-chain[4]) methods are X-chains of length 4. Uncheck this method and check x-chain: It will find all.
Also an X-wing (fish) is a small/special skyscraper.
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