Stadium: Court 16 Round: 25 Ground: Hardcourt outdoor
| ITF - Kashiwa M15 | 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 - Kashiwa M15 | 2019/04/07 03:30 | Yuki Mochizuki v Jumpei Yamasaki | 2-6,6-2,2-6 |
| ITF - Kashiwa M15 | 2019/04/05 01:00 | Cheong-Eui Kim v Jumpei Yamasaki | 4-6,6-3,4-6 |
| ITF - Kashiwa M15 | 2019/04/04 01:00 | Issei Okamura v Jumpei Yamasaki | 3-6,2-6 |
| ITF - Kashiwa M15 | 2019/04/03 06:15 | Jumpei Yamasaki v Ji Sung Nam | 6-3,2-6,7-6 |
| ITF - Tsukuba M15 | 2019/03/31 02:00 | Jumpei Yamasaki v Shintaro Imai | 4-6,4-6 |
| ITF - Tsukuba M15 | 2019/03/30 01:00 | Mick Veldheer v Jumpei Yamasaki | 2-6,2-6 |
| ITF - Tsukuba M15 | 2019/03/29 01:00 | Gage Brymer v Jumpei Yamasaki | 3-6,7-6,5-7 |
| ITF - Tsukuba M15 | 2019/03/28 01:00 | Yunosuke Tanaka v Jumpei Yamasaki | 2-6,6-1,3-6 |
| ITF M25 Matsuyama | 2019/04/09 02:40 | Issei Okamura v Shota Iino | 6-2,6-2 |
| ITF - Kashiwa M15 | 2019/04/04 01:00 | Issei Okamura v Jumpei Yamasaki | 3-6,2-6 |
| ITF - Kashiwa M15 | 2019/04/02 05:50 | Taisei Ichikawa v Issei Okamura | 7-5,5-7,5-7 |
| ITF - Tsukuba M15 | 2019/03/27 03:25 | Issei Okamura v Naoki Tajima | 3-6,4-6 |
| ITF M15 Kofu | 2019/03/22 02:00 | Issei Okamura v Ryota Tanuma | 4-6,2-6 |
| ITF M15 Kofu | 2019/03/21 02:00 | Takuya Kumasaka v Issei Okamura | 1-6,2-6 |
| ITF M15 Kofu | 2019/03/19 02:50 | Aoran Wang v Issei Okamura | 2-6,6-4,4-6 |
| ITF - Nishi-Tokyo M15 | 2019/03/13 05:25 | Rimpei Kawakami v Issei Okamura | 6-2,6-1 |