Cikakken jumla mai zuwa: Tunanin sadaukar da pawn tare da... b5 da... a6 tsoho ne. Karel Opočenský ya yi amfani da ra'ayin, a tsakanin wasu, Gideon Ståhlberg a Poděbrady 1936, Paul Keres a Pärnu 1937, Erich Eliskases a Prague 1937, da Theo van Scheltinga a gasar Olympics ta Chess ta Buenos Aires 1939. Daga baya, wasan Mark Taimanov da David Bronstein a Gasar 'Yan Takara, Zürich 1953, ya jawo hankali. Yawancin waɗannan wasannin sun fara ne a matsayin Indiyawan Sarki, tare da Black kawai daga baya suna wasa... c5 da... b5. Wataƙila wasan farko da ke amfani da daidaitattun 1.d4 Nf6 2.c4 c5 3.d5 b5 shine Thorvaldsson <unk> Vaitonis,
Wasannin Olympics na Munich na shekara ta 1936.