# 2011 Kōfu International Open – Singles

Sachie Ishizu was the defending champion, but lost to Tamarine Tanasugarn in the second round. Chang Kai-chen won the title, defeating Mandy Minella 6–4, 1–6, 6–4 in the final.

## Seeds

* Tamarine Tanasugarn (semifinals)
* Erika Sema (semifinals)
* Noppawan Lertcheewakarn (first round)
* Chang Kai-chen (champion)
* Mandy Minella (final)
* Yurika Sema (quarterfinals)
* Junri Namigata (quarterfinals)
* Aiko Nakamura (first round)

## Main 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 | Tamarine Tanasugarn | 3 | 2 | | | | | | |
| 5 | Mandy Minella | 6 | 6 | | | | | | |
| 5 | Mandy Minella | 6 | 6 | | 5 | Mandy Minella | 4 | 6 | 4 |
| | | | | | 4 | Chang Kai-chen | 6 | 1 | 6 |
| 4 | Chang Kai-chen | 6 | 4 | 6 | 4 | Chang Kai-chen | 6 | 1 | 6 |
| 2 | Erika Sema | 4 | 6 | 4 | | | | | |

### 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 |
| 1 | T Tanasugarn | 6 | 6 | | | | | | | | | | | | | | | |
| WC | R Ozaki | 3 | 4 | | 1 | T Tanasugarn | 6 | 6 | | | | | | | | | | |
| | S Ishizu | 6 | 6 | | | S Ishizu | 1 | 3 | | | | | | | | | | |
| Q | Y Miyazaki | 2 | 4 | | | | | | | 1 | T Tanasugarn | 6 | 6 | | | | | |
| | C Ogi | 1 | 2 | | | | | | | | A Omae | 3 | 4 | | | | | |
| | A Omae | 6 | 6 | | | A Omae | 7 | 6$^6$ | 7$^7$ | | | | | | | | | |
| WC | R Sawayanagi | 1 | 6 | 6 | WC | R Sawayanagi | 5 | 7$^8$ | 6$^2$ | | | | | | | | | |
| 8 | A Nakamura | 6 | 4 | 3 | | | | | | | | | | | 1 | T Tanasugarn | 3 | 2 |
| 3 | N Lertcheewakarn | 6 | 0 | 2 | | | | | | | | | | | 5 | M Minella | 6 | 6 |
| | C Takayama | 4 | 6 | 6 | | C Takayama | 6$^5$ | 6 | 6 | | | | | | | | | |
| | E Takao | 7$^7$ | 4 | 2 | | M Eguchi | 7$^7$ | 1 | 2 | | | | | | | | | |
| | M Eguchi | 6$^2$ | 6 | 6 | | | | | | | C Takayama | 0 | 6 | 2 | | | | |
| | H Watanabe | 7$^{10}$ | 3 | 6$^4$ | | | | | | 5 | M Minella | 6 | 4 | 6 | | | | |
| Q | Y Sakai | 6$^8$ | 6 | 7$^7$ | Q | Y Sakai | 1 | 0 | | | | | | | | | | |
| | K Hisami | 1 | 2 | | 5 | M Minella | 6 | 6 | | | | | | | | | | |
| 5 | M Minella | 6 | 6 | | | | | | | | | | | | | | | |

### 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 | Semifinals |
| 7 | J Namigata | 6 | 6 | | | | | | | | | | | | | | | | |
| WC | M Minokoshi | 0 | 1 | | 7 | J Namigata | 6 | 5 | 7 | | | | | | | | | | |
| | N Hamamura | 7$^7$ | 1 | 1 | | W-h Hsu | 2 | 7 | 5 | | | | | | | | | | |
| | W-h Hsu | 6$^5$ | 6 | 6 | | | | | | 7 | J Namigata | 6 | 3 | 4 | | | | | |
| | A Oka | 6 | 5 | 5 | | | | | | 4 | K-c Chang | 2 | 6 | 6 | | | | | |
| | A Yonemura | 2 | 7 | 7 | | A Yonemura | 3 | 1 | | | | | | | | | | | |
| | C-w Chan | 3 | 2 | | 4 | K-c Chang | 6 | 6 | | | | | | | | | | | |
| 4 | K-c Chang | 6 | 6 | | | | | | | | | | | | 4 | K-c Chang | 6 | 4 | 6 |
| 6 | Y Sema | 6 | 6 | | | | | | | | | | | | 2 | E Sema | 4 | 6 | 4 |
| | Y Koshino | 4 | 4 | | 6 | Y Sema | 6 | 6 | | | | | | | | | | | |
| WC | Y Tanaka | 4 | 6 | 6 | WC | Y Tanaka | 1 | 1 | | | | | | | | | | | |
| Q | M Ayukawa | 6 | 0 | 2 | | | | | | 6 | Y Sema | 0 | 6 | 3 | | | | | |
| Q | A Yamasoto | 5 | 6 | 3 | | | | | | 2 | E Sema | 6 | 4 | 6 | | | | | |
| | R Tezuka | 7 | 4 | 6 | | R Tezuka | 2 | 0 | | | | | | | | | | | |
| | M Tanaka | 0 | 2 | | 2 | E Sema | 6 | 6 | | | | | | | | | | | |
| 2 | E Sema | 6 | 6 | | | | | | | | | | | | | | | | |