| Koichi Tanaka | |
| Other Names: | Super Red Slayer Guy |
| Birth Date: | 20 October 1971 |
| Birth Place: | Japan |
| Nationality: | Japanese |
| Weight: | 145lb |
| Weight Class: | Welterweight Lightweight Featherweight Bantamweight |
| Team: | Red Sword Gym |
| Years Active: | 1997 - 2012 |
| Mma Subwin: | 3 |
| Mma Subloss: | 5 |
| Mma Decloss: | 6 |
| Mma Draw: | 1 |
| Sherdog: | 1243 |
Koichi Tanaka (born October 20, 1971) is a Japanese[1] mixed martial artist.[2] He competed in the Featherweight division.
|-| Win| align=center| | Manabu Kano| Submission (rear-naked choke)| Deep: Osaka Impact| | align=center| 2| align=center| 1:50| Osaka, Japan| |-| Loss| align=center| 2–11–1| Yuichi Miyagi| Decision (unanimous)| Pancrase: Rising 1| | align=center| 2| align=center| 5:00| Osaka, Japan| |-| Loss| align=center| 2–10–1| Kenji Takeshige| Submission (toe hold)| Pancrase: Blow 8| | align=center| 2| align=center| 2:38| Osaka, Japan|Lightweight bout.|-| Loss| align=center| 2–9–1| Hiroshi Komatsu| Decision (unanimous)| Shooto: Gig West 2| | align=center| 2| align=center| 5:00| Osaka, Japan|Bantamweight bout.|-| Loss| align=center| 2–8–1| Akitoshi Tamura| Decision (unanimous)| Shooto: Gig East 5| | align=center| 2| align=center| 5:00| Tokyo, Japan| |-| Loss| align=center| 2–7–1| Makoto Ishikawa| Decision (unanimous)| Shooto: Gig East 3| | align=center| 2| align=center| 5:00| Tokyo, Japan|Return to Featherweight.|-| Loss| align=center| 2–6–1| Yoshihiro Fujita| Technical Submission (armbar)| Shooto: Gig West 1| | align=center| 1| align=center| 3:58| Osaka, Japan|Bantmaweight debut.|-| Loss| align=center| 2–5–1| Chikara Miyake| Submission (rear-naked choke)| Shooto: Renaxis 5| | align=center| 1| align=center| 2:16| Kadoma, Osaka, Japan| |-| Loss| align=center| 2–4–1| Yohei Nanbu| Decision (majority)| Shooto: Renaxis 3| | align=center| 2| align=center| 5:00| Setagaya, Tokyo, Japan|Return to Featherweight.|-| Loss| align=center| 2–3–1| Isao Tanimura| Decision (majority)| Shooto: Shooter's Passion| | align=center| 2| align=center| 5:00| Setagaya, Tokyo, Japan|Welterweight debut.|-| Win| align=center| 2–2–1| Patrick Madayag| Submission (rear-naked choke)| SB 10: SuperBrawl 10| | align=center| 1| align=center| 10:34| Guam| |-| Loss| align=center| 1–2–1| Jutaro Nakao| Submission (triangle choke)| Shooto: Shooter's Dream| | align=center| 1| align=center| 3:56| Setagaya, Tokyo, Japan|Return to Lightweight.|-| Draw| align=center| 1–1–1| Masato Fujiwara| Draw| Shooto: Las Grandes Viajes 3| | align=center| 2| align=center| 5:00| Tokyo, Japan|Featherweight debut.|-| Loss| align=center| 1–1| Tetsuji Kato| Technical Submission (armbar)| Shooto: Las Grandes Viajes 1| | align=center| 1| align=center| 1:01| Tokyo, Japan| |-| Win| align=center| 1–0| Tae Yoon Han| Submission (rear-naked choke)| CMA: Octagon Challenge| | align=center| 1| align=center| 0:38| Nagoya, Aichi, Japan|