
.) create my own guided KeyCell-ramify strategy, starting with
	selected cell w/only 2 digits as candidates (for x1.txt).
	Motivation: if 7@11 is selected, puzzle solves itself.
	Perhaps if 2 is selected, we can easily find a contradiction
	or a blank cell (no candidates left).

	I don't see that this would be any less-respectable
	than Ywing, linkedPairs or Xcycles. They all involve
	shotgunning for a starting supposition that leads 
	to a contradiction.

============================================================

.) steps to solve x1 (from sudokuWiki.org):

		Next need "hidden unique rectangle" (sudokuWiki.org)
		.) hidden unique rectangle: 6@86
		.) alternate inference chain [AIC]: 3@55...assuming On =>
			88-33-66-64-55
		.) AIC: 1@99-55-11-18-48-98 =><=
		.) boxline-reduct.: 2@91-11-99 =><=
		.) AIC: 2@32-11-66-62-32 =><=
		.) 2 in col1 box 1 => no 2@81
		.) AIC: 3@92-99-11-66-62-52-92 =><=
		.) AIC: 3@86-88-28-19-14-84-86 =><=
		.) AIC: 3@98-99-11-18-48-98 =><=
		.) gXcycles: offORon3@98=>3@box9col3-28 Ok but 3@82 sees both 28/88 3's
			either way 3@82 must be OFF.
		.) now have naked pair box7 of {2,8}...flush box7.
		.) now have pair 8's on Bdiag...remove 8@86
		.) 8@94 removed from linkedPairs(8), then again linkedPairs(8)
			can remove 8's at 76, 87, 89
		.) 3D medusa then removes many digits...
		Then f-key + u-key finishes.


