Bidirectional X-Cycle{2}

The cells {0} form a bidirectional cycle: there are exactly two ways of placing the value {1} in these cells, forming two different possible configurations. Some {1}s appear in a row, column or box regardless of which configuration is correct. Because one of the two configurations must be correct, other occurrences of the value {1} can be removed from these rows, columns or boxs.

The cycle is an X-Cycle because only a single value is involved. X is a value, so it's a variable, if you think that way. Bidirectional X-Cycles are also known as Fishy Cycles or Bilocation cycles.

The two configurations of the bidirectional cycle are enforced by two complementary, circular chains of implications. The details of each chain are given below.

Cycle details, forward direction (View 1):
{3}

Cycle details, reverse direction (View 2):
{4}

NOTE: if all hinters are selected all Bidirectional X-Cycles should (AFAIK) be found BEFORE we call the Unary Chainer, So you should (AFAIK) never see an X-Cycle hint. If all hinters are selected AND you're seeing an X-Cycle, then one of the previous (simpler) hinters has missed a trick!