# 2020 Shimadzu All Japan Indoor Tennis Championships – Singles

Ylena In-Albon was the defending champion, but chose not to participate.
Xun Fangying won the title, defeating Indy de Vroome in the final, 3–6, 6–3, 7–6$^{(8–6)}$.

## Seeds

* Wang Xinyu (semifinals)
* Arina Rodionova (first round)
* Xun Fangying (champion)
* Indy de Vroome (final)
* Kyōka Okamura (second round)
* Akiko Omae (quarterfinals)
* Peangtarn Plipuech (first round)
* Ayano Shimizu (quarterfinals)

## Draw
### Key

* Q = Qualifier
* WC = Wild card
* LL = Lucky loser
* Alt = Alternate
* SE = Special exempt
* PR = Protected ranking
* ITF = ITF entry
* JE = Junior exempt
* w/o = Walkover
* r = Retired
* d = Defaulted
* SR = Special ranking

### Finals

| Semifinals | Semifinals | Semifinals | Semifinals | Semifinals | Final | Final | Final | Final | Final |
| 1 | Wang Xinyu | 6 | 4 | 3 | | | | | |
| 4 | Indy de Vroome | 3 | 6 | 6 | | | | | |
| 4 | Indy de Vroome | 3 | 6 | 6 | 4 | Indy de Vroome | 6 | 3 | 6$^6$ |
| | | | | | 3 | Xun Fangying | 3 | 6 | 7$^8$ |
| 3 | Xun Fangying | 6 | 6 | | 3 | Xun Fangying | 3 | 6 | 7$^8$ |
| Q | Erina Hayashi | 1 | 2 | | | | | | |

### Top half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 1 | Xin Wang | 6 | 6 | | | | | | | | | | | | | | | | |
| WC | S Oshino | 3 | 2 | | 1 | Xin Wang | 6 | 6 | | | | | | | | | | | |
| | J Namigata | 4 | 4 | | | N Hanatani | 1 | 4 | | | | | | | | | | | |
| | N Hanatani | 6 | 6 | | | | | | | 1 | Xin Wang | 4 | 6 | 6 | | | | | |
| | M Hontama | 1 | 6 | 6 | | | | | | 8 | A Shimizu | 6 | 1 | 2 | | | | | |
| | H Kaji | 6 | 1 | 3 | | M Hontama | 7 | 3 | 4 | | | | | | | | | | |
| WC | M Kato | 4 | 3 | | 8 | A Shimizu | 5 | 6 | 6 | | | | | | | | | | |
| 8 | A Shimizu | 6 | 6 | | | | | | | | | | | | 1 | Xin Wang | 6 | 4 | 3 |
| 4 | I de Vroome | 6 | 6 | | | | | | | | | | | | 4 | I de Vroome | 3 | 6 | 6 |
| Q | K Yoshioka | 1 | 3 | | 4 | I de Vroome | 6 | 6 | | | | | | | | | | | |
| Q | Yi Zhang | 6 | 3 | 7$^7$ | Q | Yi Zhang | 2 | 4 | | | | | | | | | | | |
| | E Hozumi | 2 | 6 | 6$^1$ | | | | | | 4 | I de Vroome | 7$^9$ | 6 | | | | | | |
| | N Sato | 3 | 5 | | | | | | | Q | J Kang | 6$^7$ | 1 | | | | | | |
| Q | J Kang | 6 | 7 | | Q | J Kang | 6 | 6 | | | | | | | | | | | |
| | T Moore | 7$^7$ | 6 | | | T Moore | 1 | 3 | | | | | | | | | | | |
| 7 | P Plipuech | 6$^4$ | 2 | | | | | | | | | | | | | | | | |

### Bottom half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 6 | A Omae | 6 | 6 | | | | | | | | | | | | | | | |
| | M Kobori | 2 | 1 | | 6 | A Omae | 6 | 6 | | | | | | | | | | |
| | M Uchijima | 6$^4$ | 6 | 7$^7$ | | M Uchijima | 1 | 2 | | | | | | | | | | |
| | M Imanishi | 7$^7$ | 3 | 6$^3$ | | | | | | 6 | A Omae | 3 | 7 | 5 | | | | |
| Q | C Hosonuma | 6 | 6 | | | | | | | 3 | F Xun | 6 | 5 | 7 | | | | |
| | M Ayukawa | 3 | 4 | | Q | C Hosonuma | 2 | 4 | | | | | | | | | | |
| | E Bektas | 4 | 3 | | 3 | F Xun | 6 | 6 | | | | | | | | | | |
| 3 | F Xun | 6 | 6 | | | | | | | | | | | | 3 | F Xun | 6 | 6 |
| 5 | K Okamura | 6 | 6 | | | | | | | | | | | | Q | E Hayashi | 1 | 2 |
| | H Kuwata | 1 | 3 | | 5 | K Okamura | 1 | 6 | 4 | | | | | | | | | |
| | H Arakawa | 6 | 2 | 6$^3$ | Q | E Hayashi | 6 | 4 | 6 | | | | | | | | | |
| Q | E Hayashi | 2 | 6 | 7$^7$ | | | | | | Q | E Hayashi | 6 | 6 | | | | | |
| Q | A Matsumoto | 5 | 2 | | | | | | | | R Ushijima | 0 | 2 | | | | | |
| | M Yamaguchi | 7 | 6 | | | M Yamaguchi | 6 | 6$^5$ | 2 | | | | | | | | | |
| | R Ushijima | 6 | 1 | 7$^7$ | | R Ushijima | 2 | 7$^7$ | 6 | | | | | | | | | |
| 2 | Ar Rodionova | 4 | 6 | 6$^3$ | | | | | | | | | | | | | | |