From Sudopedia, the free Sudoku reference guide

From Sudopedia

A limited form of Trial & Error where only constraints with 2 remaining candidates are considered.

When there are only 2 candidates left for a constraint, one of them must be true and the other must be false. In bifurcation, both branches of the fork are tried by placing the candidate in its cell and solving the puzzle from that point forward. When a contradiction is found, the remaining candidate can be placed.

Bifurcation has a bad reputation in the Sudoku community because it relies on backtracking and looks similar to guessing. Many advanced solving techniques were introduced to reduce the need for bifurcation.

The topic in this article is a still a subject of debate. Parts of the text may not express everybody's opinion. Use the associated Talk page if you do not agree with the opinion of the writer, rather than continuously editing the main article.