On August 12, 1946 — Stan Musial gets four hits in four at-bats against the Chicago Cubs, giving Musial 12 hits over three games. The St. Louis Cardinals win, 5 – 0, behind Al Brazle’s three-hitter.

Source:
Baseball Reference August 12
National Pastime
Retro Sheet
Hall of Fame
SABR Games Project
Replay The Game