Jun Koseki boxer
- bouts
- 13
- won
- 8
- lost
- 5
- draw
- 0
- Status
- inactive
- Division
- bantamweight
- Debut
- 2009-07-13
- Height
- -
- Reach
- -
- Age
- -
- Born
- 1990-02-26
- Death
- -
- Nationality
- Japan
| Date | Opponent | Last Opponents' Results | Place | Result |
|---|---|---|---|---|
| 2016-09-13 | Keita Kurihara | WLLWWW | Korakuen Hall | LOST Technical knockout |
| 2016-03-17 | Yuki Nakai | LDWWLW | Korakuen Hall | WIN Split-decision |
| 2014-08-08 | Joe Tanooka | WWWWLW | Korakuen Hall | LOST Majority decision |
| 2014-03-05 | Yoshiyuki Yamaguchi | WDWLWL | Korakuen Hall | LOST Unanimous decision |
| 2013-08-25 | Takuya Mori | WWWWL | Ariake Colosseum | WIN Split-decision |
| 2013-04-12 | Ryu Kenshiro | DWWLLW | Korakuen Hall | WIN Technical knockout |
| 2013-01-31 | Ryuji Hirano | WDWWLW | Korakuen Hall | WIN Majority decision |
| 2012-08-07 | Yuta Saito | LWLLWW | Korakuen Hall | LOST Unanimous decision |
| 2012-01-30 | Yuki Ishizaki | WW | Korakuen Hall | WIN Unanimous decision |
| 2011-09-28 | Shohei Kikuzato | WWW | Korakuen Hall | LOST Unanimous decision |
| 2011-07-29 | Masanori Shimizu | WLLWL | Korakuen Hall | WIN Majority decision |
| 2010-09-30 | Makoto Sugaizumi | LW | Korakuen Hall | WIN KO |
| 2009-07-13 | Mikiya Ishikawa | W | Korakuen Hall | WIN Technical knockout |