Kuboya was one of four players tied in the lead heading into today's final round but through nine holes it was he and Plaphol who had drawn clear.
Ahead on the golf course Queenslander Kennedy, in his rookie Japan Tour season, was making a big move. In 24th position overnight he moved through the field with a bogey final round of 65 (the best of the day) to complete what would be his best finish of the year.
Kennedy started some 90 minutes ahead of the final group so had an agonising wait to see whether he might have done enough to at least force a playoff.
Kuboya birdied the 13th and 17th holes to edge ahead and but Kennedy would finish in a share of 2nd and earn Ã¯Â¿Â¥10,800,000 (A$140,000) perhaps the biggest cheque of his career behind the massive US$180,000 for finishing third at the Singapore Open in 2006.
Kennedy now moves to 20th on the 2011 Japan Tour money list with earnings of (equiv)A$430,000.
Brendan Jones finished 11th, Neven Basic 24th, Chris Campbell 50th and Kurt Barnes 55th.
Money list leader Bae Sang-moon missed the cut this week.
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