Shin Tae-yong's team successfully defended the title with their second consecutive win of the competition having starting the campaign with a draw against China before defeating North Korea to finish a point ahead of fellow World Cup qualifiers Japan.
The defeat was the worst the Japanese have suffered at the hands of the South Koreans on home soil since a 5-1 loss against their great rivals in Tokyo in 1954, the countries' first ever international meeting.
"We won and that's very good for us, but even though we won I think there is room for improvement and we would like to improve the Korean team so we can perform well at the World Cup," said Shin.
"We had to win today, so there was pressure. Immediately after the start we conceded a goal from the penalty, but the players pulled together and were able to come from behind and win, so I'm proud of my players."
Kim scored twice in the first half, levelling the scores with a header after Yu Kobayashi had given Japan a third minute lead from the penalty spot.
A free kick from Jung Woo-young and a second goal from Kim in the 35th minute put the Koreans in front at half-time before another free kick from Yeom Ki-hun put the seal on a comprehensive win.
Both nations were under strength during the competition, with neither nation able to select their Europe-based players due to the tournament not being held during FIFA international dates.
Earlier in the evening, China sealed third place in the competition after Marcello Lippi's side were held to a 1-1 draw by North Korea.
Wei Shihao scored his second goal in just his third appearance for China in the 28th minute when he finished off a rapid counterattack, but Jong Il Gwan's free kick nine minutes from time earned the North Koreans a share of the points.
"I want to be able to form a new team, a new squad for the future," said Lippi.
"The result was very good and I'm very happy about that."
(Reporting by Michael Church; Editing by Stephen Powell)
