Stadium: Court 5 Round: 25 Ground: Hardcourt outdoor
| ITF M15 Kofu | 2019/03/18 06:30 | Keigo Shimizu v Seita Watanabe | 1-6,1-6 |
| ITF M15 Kofu | 2019/03/18 03:00 | Seita Watanabe v Shao-Fan Liu | 6-3,4-6,11-9 |
| ITF M15 Nishi-Tokyo | 2019/03/12 05:00 | Makoto Ochi v Seita Watanabe | 6-1,6-2 |
| Challenger Kobe | 2018/11/11 06:10 | Blake Ellis v Seita Watanabe | 6-4,6-2 |
| Challenger Kobe | 2018/11/10 07:20 | Seita Watanabe v Takashi Saito | 4-6,7-5,7-6 |
| ITF Japan F8 | 2018/06/09 01:00 | Seita Watanabe v Tomohiro Masabayashi | 7-6,5-7,4-6 |
| Challenger Kobe Qual | 2017/11/04 07:45 | Seita Watanabe v Xin Gao | 6-4,4-6,0-6 |
| ITF M15 Nishi-Tokyo | 2019/03/12 03:20 | Ryota Tanuma v Sho Katayama | 6-4,2-6,10-5 |
| ITF M15 Nishi-Tokyo | 2019/03/11 01:00 | Shota Tange v Sho Katayama | 3-6,3-6 |
| ITF M15 Nishi-Tama | 2019/03/07 04:00 | Shintaro Imai v Sho Katayama | 6-2,6-3 |
| ITF M15 Nishi-Tama | 2019/03/06 02:25 | Sho Katayama v Yuta Kawahashi | 6-3,6-1 |
| ITF M15 Nishi-Tama | 2019/03/05 03:00 | Sho Katayama v Yuta Kawahashi | 4-6,5-7 |
| ITF M15 Nishi-Tama | 2019/03/05 01:00 | Sho Katayama v Masayoshi Ono | 6-4,6-4 |
| ITF Canada F7 | 2018/09/12 14:00 | Jack Findel-Hawkins v Sho Katayama | 6-3,6-3 |
| ITF Canada F7 | 2018/09/11 19:45 | Emmett Ward v Sho Katayama | 1-6,1-6 |