 One line he picked up from Bohatirchuk was the Chigorin Variation against the French Defence (1.e4 e6 2.Qe2), and he played this with success.During his peak years, his use of the Modern Defence placed him near the leading edge of world research there; he developed the Pterodactyl Variation and used it with success against strong players.Other favorite lines were the Closed Variation of the Sicilian Defence, the Grand Prix Attack against the Sicilian, and the Old Indian Defence.