Japan's oldest active player, Chunichi Dragons lefty Masahiro Yamamoto, said Sunday that he expects to improve this year and become the oldest winning pitcher in Nippon Professional Baseball history.

Speaking at an event in Nagoya, the Chunichi Dragons pitcher, who turned 48 last August, said, "I have a lot of breaking balls I'm eager to try out. Although I'll be one year older, I want to do better than last year."

Yamamoto went 5-2 last season in 16 games and posted a 4.46 earned run average in 2013.

In April 2012, he became the oldest starting pitcher to win a game, at the age of 46 years, eight months and four days, and last year extended that record. The man whose record Yamamoto broke, Hankyu Braves player-manager Shinji Hamazaki, set the record for the oldest pitcher to win a game, when he won in relief at the age of 48 years, four months.

"I want (people to see) a new Japan record," said the pitcher.

When Yamamoto signed his contract for the 2014 season, Dragons general manager Hiromitsu Ochiai asked him to keep at it until he turns 50, but the pitcher said it is not that easy.

"My margin for error now is a very fine line," he said. "Should I fail this year, I feel inside that I'll have to make some hard choices."