During 1937, Bican left Vienna to join Czech club Slavia Prague. He played for Slavia throughout World War II, while many of his football rivals were at war. During eight league seasons he would score 328 goals, including 57 in 26 matches one particular season. Three times in his career, Bican scored seven goals in a game. In a 1939–40 league match against Zlín, Bican found the net seven times as Slavia ran out 10–1 winners. During the 1940–41 season, Bican matched his feat of the previous season, again against Zlín, scoring seven times, as Slavia won by a 12–1 scoreline. It was 1947–48 before Bican managed his third seven-goal match, as Slavia defeated České Budějovice in a game which finished 15–1.