Stadium: Court 16 Round: 25 Ground: Hardcourt outdoor
| ITF - M15 Kashiwa | 2019/04/04 01:00 | Issei Okamura v Jumpei Yamasaki | 3-6,2-6 |
| ITF Thailand F3 | 2016/09/07 02:00 | Issei Okamura v Jumpei Yamasaki | 6-4,2-6,4-6 |
| ITF - M15 Kashiwa | 2019/04/07 03:30 | Yuki Mochizuki v Jumpei Yamasaki | 2-6,6-2,2-6 |
| ITF - M15 Kashiwa | 2019/04/05 01:00 | Kim, Cheong-Eui v Jumpei Yamasaki | 4-6,6-3,4-6 |
| ITF - M15 Kashiwa | 2019/04/04 01:00 | Issei Okamura v Jumpei Yamasaki | 3-6,2-6 |
| ITF - M15 Kashiwa | 2019/04/03 06:15 | Jumpei Yamasaki v Nam, Ji Sung | 6-3,2-6,7-6 |
| ITF - M15 Tsukuba | 2019/03/31 02:00 | Jumpei Yamasaki v Shintaro Imai | 4-6,4-6 |
| ITF - M15 Tsukuba | 2019/03/30 01:00 | Veldheer, Mick v Jumpei Yamasaki | 2-6,2-6 |
| ITF - M15 Tsukuba | 2019/03/29 01:00 | Brymer, Gage v Jumpei Yamasaki | 3-6,7-6,5-7 |
| ITF - M15 Tsukuba | 2019/03/28 01:00 | Tanaka, Yunosuke v Jumpei Yamasaki | 2-6,6-1,3-6 |
| Matsuyama, Singles M-ITF-JPN-06A | 2019/04/09 02:40 | Issei Okamura v Iino, Shota | 6-2,6-2 |
| ITF - M15 Kashiwa | 2019/04/04 01:00 | Issei Okamura v Jumpei Yamasaki | 3-6,2-6 |
| ITF - M15 Kashiwa | 2019/04/02 05:50 | Taisei Ichikawa v Issei Okamura | 7-5,5-7,5-7 |
| ITF - M15 Tsukuba | 2019/03/27 03:25 | Issei Okamura v Naoki Tajima | 3-6,4-6 |
| Kofu, Qualifications Simples M-ITF-JPN-03A | 2019/03/22 02:00 | Issei Okamura v Ryota Tanuma | 4-6,2-6 |
| Kofu, Qualifications Simples M-ITF-JPN-03A | 2019/03/21 02:00 | Takuya Kumasaka v Issei Okamura | 1-6,2-6 |
| Kofu, Qualifications Simples M-ITF-JPN-03A | 2019/03/19 02:50 | Aoran Wang v Issei Okamura | 2-6,6-4,4-6 |
| ITF - M15 Nishi-Tokyo | 2019/03/13 05:25 | Kawakami, Rimpei v Issei Okamura | 6-2,6-1 |