Principle of Two Weaknesses

This principle is well attested in modern training literature but its origin is not, and the most commonly repeated attribution could not be verified. Mark Dvoretsky, writing in his column The Instructor, calls the two weaknesses principle one of the most important techniques for exploiting an advantage, and points readers to Endgame Strategy by Mikhail Shereshevsky, Technique for the Tournament Player by Dvoretsky and Yusupov, and his own School of Chess Excellence 1: Endgame Analysis. Notably, Dvoretsky does not attribute the principle to any earlier author, and describes it in terms of creating a second weakness and opening a second front. Popular chess websites frequently credit Nimzowitsch with formulating the principle in My System, but no source fetched in this research supports that, and neither Wikipedia's article on My System nor its biography of Nimzowitsch lists the two weaknesses principle among his contributions. The phrase is also absent from Wikipedia's chess glossary. The attribution should therefore be treated as unverified.

First documented: n.a. — n.a. — the earliest source located here is Mark Dvoretsky, The Two Weaknesses Principle, in his column The Instructor, which cites Shereshevsky's Endgame Strategy and Dvoretsky and Yusupov's Technique for the Tournament Player as prior treatments without naming an originator