Semyon Zinovyevich Alapin (Russian: Семён Зиновьевич Алапин; 19 November [O.S.

7 November] 1856 – 15 July 1923) was a Russian chess player, openings analyst, and puzzle composer.

Born in Saint Petersburg, Russia, into a Jewish family on 19 November [O.S.

He was one of the strongest chess players in the Russian Empire in the late 19th century.

Most of these are of little significance today, but Alapin's Variation of the Sicilian Defence is an important opening line that is often played by leading grandmasters.