His brother Akio Ishii was drafted in 1986 but never made it into Nippon Pro Baseball.

He allowed eight hits and four runs (three earned) in 5 2/3 IP in the 1997 Japan Series, but the team fell to the Yakult Swallows.

He tied Tomohiro Kuroki for second in the circuit in ERA behind Satoru Kanemura but failed to make the All-Star team.

Among Seibu's regularly-used starting pitchers, only Chih-Chia Chang had a better ERA while Ishii out-pitched Koji Mitsui, Nishiguchi, Ming-Chieh Hsu, Shiozaki and Matsuzaka.

Seibu was swept in the 2002 Japan Series by the Yomiuri Giants; Ishii started and lost game two.

Matsuzaka, Nishiguchi, Chang and Kazuyuki Hoashi all had better regular seasons, but Seibu skipper [[Tsutomu Itō ]] still went with Ishii to start game one of the 2004 Japan Series.

Ishii again pitched shutout ball to get the win (his bullpen did allow two late runs).

He finished 2-0 with 13 scoreless innings and only five hits for the Series, having won more games than he had in the entire regular season, something no one had ever done before.

Overall, Takashi Ishii was 68-58 with 13 saves and a 3.78 ERA in 321 games in Nippon Pro Baseball.