When using a candidate table to solve a sudoku, several methods reduce the table. The difficulty levels map to the methods: Super easy = SiSo, Very easy = SC, Easy = SB, Medium = DS, Hard = DC, Harder = XW, Very hard = SF/JF/SqB/NS, Super hard = iteration.
Print a ready-to-use solving table
IG
Initial grid — initialises the solving table.
SiSo
Single solution — fills the obvious cells.
SC
Single cell — the only cell that can hold a digit.
SB
Single box — the only box that can hold a digit.
DS
Disjoint subset — x cells with the same x candidates.
DC
Disjoint chain — x candidates spread across x cells.
XW
X-Wing
SF
Swordfish
JF
Jellyfish
SqB
Squirmbag
NS
Nishio
BB
Bowman Bingo