Hamaguchi is from the town of Kiyama in Saga Prefecture. The town is planning to present Hamaguchi with their Citizen Honor Award. He will be the third person to receive the award.
October 4, 2017 vs Chunichi at Yokohama Stadium – Hamaguchi notched his tenth victory of the year and became the sixth Yokohama rookie pitcher to reach double-digits in wins, first since Takeo Kawamura in 1997; and the first Yokohama left-handed rookie to reach double-digits in wins since Takashi Suzuki in 1958.
October 19, 2017 vs Hiroshima at Mazda Stadium – Hamaguchi recorded the win and became the ninth rookie (accomplished eleven times) in Playoff/Climax Series history to notch a win. He is the first rookie in Yokohama Bay Stars history to record a post-season victory.
Hamaguchi recorded two wild pitches in the game (first and second inning) and became the fifth player (accomplished five times) to throw two wild pitches in one Player/Climax Series game. He joined Kenichi Nakata (2007, Final Stage, Game 3) as the only players to record two wild pitches in one game and get the win.
Source: Sponichi 10/20/2017
November 1, 2017 vs Softbank at Yokohama Stadium – Hamaguchi had a no-hitter until he gave up a one-out double to Shinya Tsuruoka in the 8th inning. He picked up the win and became the sixteenth rookie in NPB history to record a Nippon Series victory, first since Tomoyuki Sugano in 2013 and first in Yokohama Bay Stars history. He also became the fourth pitcher (rookie and otherwise) to carry a no-hitter through at least 7.1 innings of work. The other three: Daisuke Yamai (8.0 in 2007), Minoru Murayama (7.1 innings in 1962), and Shinji Sasaoka (7.1 innings in 1991).
Source: Sponichi 11/2/2017