Grouped AIC

An alternating inference chain that links through box/line groups.

Learn the Grouped AIC technique: an alternating inference chain whose nodes can be a group of a digit’s cells in a box-line intersection.

How to use it

1. Allow group nodes. A group is the two or three cells of one digit that share a box and a line. The group is "on" when the digit lands in any of those cells, so it can stand in for a single node in a chain.
2. Alternate strong and weak links. Chain strong links (a unit whose digit cells split exactly between two nodes) with weak links (two nodes that cannot both hold the digit), beginning and ending on a strong link.
3. Eliminate what sees both ends. As with any AIC, at least one end is true, so a candidate that sees both ends — every cell of a group end included — is removed.