is a male badminton player from Japan.
Career
Otsuka competed in badminton at the 2004 Summer Olympics in men's doubles with partner Keita Masuda. They had a bye in the first round, then were defeated in the round of 16 by Fu Haifeng and Cai Yun of China.
He also competed in mixed doubles with partner Shizuka Yamamoto. They were defeated in the round of 32 by Robert Blair and Natalie Munt of Great Britain.
Ohtsuka played at the 2007 BWF World Championships in men's doubles with Keita Masuda, and were defeated in the third round by the eventual champions Markis Kido and Hendra Setiawan, of Indonesia, 22-20, 21-19.
Coaching and academic career
Following his retirement from competitive play, Ōtsuka transitioned into coaching and academia. He is currently an Associate Professor in the Department of Physical Education at Nippon Sport Science University.
Achievements
BWF Grand Prix (1 title, 1 runner-up)
The BWF Grand Prix had two levels, the BWF Grand Prix and Grand Prix Gold. It was a series of badminton tournaments sanctioned by the Badminton World Federation (BWF) which was held from 2007 to 2017. The World Badminton Grand Prix has been sanctioned by International Badminton Federation (IBF) from 1983 to 2006.
Men's doubles
{| class="sortable wikitable" style="font-size: 90%;"
! Year
! Tournament
! Partner
! Opponent
! Score
! Result
|-
| align="center" | 2005
| align="left" | Dutch Open
| align="left" | Keita Masuda
| align="left" | Choong Tan Fook<br /> Lee Wan Wah
| align="left" | 7–15, 4–15
| style="text-align:left; background:white" | Runner-up
|- style="background:#D4F1C5"
| align="center"| 2007
| align="left"| U.S. Open
| align="left"| Keita Masuda
| align="left"| Howard Bach<br /> Khan Malaythong
| align="left"| 21–18, 21–11
| style="text-align:left; background:white" | Winner
|}
: BWF Grand Prix tournament
: IBF World Grand Prix tournament
IBF International Challenge/Series (5 titles, 4 runners-up)
Men's doubles
{| class="sortable wikitable" style="font-size: 90%;"
! Year
! Tournament
! Partner
! Opponent
! Score
! Result
! Ref
|- style="background:#D5D5D5"
| align="center" | 1999
| align="left" | Mexico International
| align="left" | Keita Masuda
| align="left" | Ma Che Kong<br /> Yau Tsz Yuk
| align="left" | 7–15, 15–13, 10–15
| style="text-align:left; background:white" | Runner-up
|- style="background:#D5D5D5"
| align="center"| 2000
| align="left"| Cuba International
| align="left"| Keita Masuda
| align="left"| José Antonio Crespo<br/> Sergio Llopis
| align="left"| 15–9, 15–2
| style="text-align:left; background:white"| Winner
| style="text-align:center; background:white" |
|- style="background:#D5D5D5"
| align="center"| 2000
| align="left"| French International
| align="left"| Keita Masuda
| align="left"| Takuya Katayama<br/> Yuzo Kubota
| align="left"| 15–6, 15–11
| style="text-align:left; background:white"| Winner
|- style="background:#D5D5D5"
| align="center" | 2003
| align="left" | Waikato International
| align="left" | Keita Masuda
| align="left" | Hendri Saputra<br /> Denny Setiawan
| align="left" | 7–15, 15–12, 3–15
| style="text-align:left; background:white" | Runner-up
| style="text-align:center; background:white" |
|- style="background:#D5D5D5"
| align="center"| 2003
| align="left"| Guatemala International
| align="left"| Keita Masuda
| align="left"| Howard Bach<br /> Kevin Han
| align="left"| 15–6, 15–12
| style="text-align:left; background:white" | Winner
|-style="background:#D5D5D5"
| align="center" | 2004
| align="left" | Iran Fajr International
| align="left" | Keita Masuda
| align="left" | Liu Kwok Wa<br/> Albertus Susanto Njoto
| align="left" | 4–15, 11–15
| style="text-align:left; background:white" | Runner-up
|-style="background:#D5D5D5"
| align="center" | 2004
| align="left" | Mauritius International
| align="left" | Keita Masuda
| align="left" | Liu Kwok Wa<br/> Albertus Susanto Njoto
| align="left" | 15–11, 15–8
| style="text-align:left; background:white" | Winner
|}
Mixed doubles
{| class="sortable wikitable" style="font-size: 90%;"
! Year
! Tournament
! Partner
! Opponent
! Score
! Result
! Ref
|- style="background:#D5D5D5"
| align="center"| 2003
| align="left"| Mauritius International
| align="left"| Shizuka Yamamoto
| align="left"| Kristof Hopp<br/> Kathrin Piotrowski
| align="left"| 10–15, 15–7, 15–7
| style="text-align:left; background:white"| Winner
|- style="background:#D5D5D5"
| align="center" | 2003
| align="left" | Waikato International
| align="left" | Shizuka Yamamoto
| align="left" | Daniel Shirley<br /> Sara Petersen
| align="left" | 4–15, 8–15
| style="text-align:left; background:white" | Runner-up
| style="text-align:center; background:white" |