It was a match that carried a lot of political tension. Though they were the only two members in their qualification group (after China withdrew), Korean president Syngman Rhee initially refused to sanction any game against Japan due to their actions against Korea in World War II. He eventually relented, but only in part. Instead of home and away matches as required by FIFA, he demanded that both matches be played in Japan so that no "past invader" would set foot on Korean soil. He also told the Korean players "Be prepared to throw yourselves in the ocean if you lose."
Thankfully for them, that was not required, though they may have been worried when Japan took a 16th-minute lead with a goal from Ken Naganuma. But Chung Nam-Sick equalized six minutes later and Korea never looked back, getting additional goals from Choi Kwang-Suk (34'), Sung Nak-Woon (65'), and Choi Jung-Min (82', 85').
They played again in Tokyo one week later. That match ended as a 2-2 draw, which was enough to send Korea to their first World Cup in Switzerland.