Koshiro Yamamuro

Koshiro Yamamuro's pro career with the Chiba Lotte Marines came down to a single big-league appearance in 2010, and honestly that kind of understated story says something in itself. A guy from Seya, Kanagawa — that quiet suburban corner of Yokohama — who made it all the way to Aoyama Gakuin University and kept swinging, kept grinding on the diamond. Baseball in Japan at the university level is no joke — the commitment alone is a statement. He went on to run his own business after baseball, and I've got a soft spot for athletes who clearly did the work without needing a spotlight to do it.

This take was written by generative AI, one per person, from publicly reported facts (editorial policy). It is a reading of the record, not reporting.

Koshiro Yamamuro is a Japanese businessman and former professional baseball pitcher born on July 14, 1987, in Seya Ward, Yokohama, Kanagawa Prefecture. He stands 183 cm tall and pursued his baseball career through Aoyama Gakuin University. He pitched for the Chiba Lotte Marines, appearing in one NPB game in 2010, and now runs his own company.

Name (English)

Koshiro Yamamuro

Name (Japanese)

山室公志郎

Reading

やまむろ こうしろう

Born

July 14, 1987 (age 39)

Origin

Seya Ward, Kanagawa Prefecture, Japan

Height

183cm

Occupation

Baseball player

Zodiac / Chinese zodiac

Cancer / Rabbit

University

Aoyama Gakuin University

• Wikipedia (Japanese)https://ja.wikipedia.org/wiki/%E5%B1%B1%E5%AE%A4%E5%85%AC%E5%BF%97%E9%83%8E
• Wikidatahttps://www.wikidata.org/wiki/Q6433140

Tags

• From Kanagawa Prefecture
• Baseball player

Last updated

October 18, 2026

Only publicly available facts are listed; non-public or unconfirmed items are omitted. Base data was compiled from Wikidata from June 2026 onward; ages are recalculated daily and deaths are checked against Wikidata on an ongoing basis. English text is machine-assisted (facts translated by Sonnet, "My Take" written by Opus 4.8). The Japanese page is the source of record.