Ywing

定义1 Ywing

如(Y==X)--X==X--(X==Y)的链称为Ywing，是两个候选数XY的格被一条X的强链连结形成的。

Chains like (Y==X)--X==X--(X==Y), Ywing is 2 cells with candidate XY, linked by a strong chain of X.

◆标准Ywing  Classic Ywing

① 56 pairs linked by Chains of 6.

② 79 pairs linked by Chains of 7.

◆区块Ywing  Grouped Ywing

I7和I9在链上被视为一个节点。

I7 and I9 are seen as one spot on the Chain.

◆结合单链 Ywing with Chains

27数对通过2的单链连结。在这个例题中，一个节点是区块。

27 pairs linked by Chains of 2. In this example, a spot of the Chains is a Block.

练习 Practice

① 通过Ywing寻找下一步。Find out the next step by Ywing.

答案 Answer

① 如图所示（解法不唯一，仅供参考）。

As the picture shows (may be not unique answer, reference only).