# 2012 Keio Challenger – Singles

Takao Suzuki was the champion in 2009. Matteo Viola won the title by defeating Mirza Bašić 7–6$^{(7–3)}$, 6–3 in the final.

## Seeds

* Tatsuma Ito (second round)
* Rajeev Ram (quarterfinals)
* Yuichi Sugita (semifinals)
* Matteo Viola (champion)
* Hiroki Moriya (quarterfinals)
* Chen Ti (first round)
* Jamie Baker (second round)
* Brydan Klein (first round)

## 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 | Final | Final | Final | Final |
| | Taro Daniel | 0 | 4 | | | | |
| 4 | Matteo Viola | 6 | 6 | | | | |
| 4 | Matteo Viola | 6 | 6 | 4 | Matteo Viola | 7$^7$ | 6 |
| | | | | | Mirza Bašić | 6$^3$ | 3 |
| 3 | Yuichi Sugita | 4 | 0 | | Mirza Bašić | 6$^3$ | 3 |
| | Mirza Bašić | 6 | 6 | | | | |

### 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 | Semifinals | Semifinals | Semifinals | Semifinals |
| 1 | T Ito | 6 | 3 | 7$^7$ | | | | | | | | | | | | | |
| | J Millman | 4 | 6 | 6$^3$ | 1 | T Ito | 3 | 1 | | | | | | | | | |
| | Taro Daniel | 6 | 6 | | | T Daniel | 6 | 6 | | | | | | | | | |
| | Julien Obry | 0 | 3 | | | | | | | | T Daniel | 6 | 6 | | | | |
| | Andrea Arnaboldi | 6 | 4 | | | | | | | | A Arnaboldi | 2 | 3 | | | | |
| | Y Uchiyama | 1 | 0$^r$ | | | A Arnaboldi | 3 | 6 | 7 | | | | | | | | |
| | M Reid | 6 | 2 | 2 | 7 | J Baker | 6 | 1 | 5 | | | | | | | | |
| 7 | J Baker | 4 | 6 | 6 | | | | | | | | | | | T Daniel | 0 | 4 |
| 4 | M Viola | 4 | 6 | 6 | | | | | | | | | | 4 | M Viola | 6 | 6 |
| | H Laaksonen | 6 | 3 | 4 | 4 | M Viola | 6 | 4 | 7 | | | | | | | | |
| Q | Y Ito | 3 | 6 | 3 | | B Mitchell | 3 | 6 | 5 | | | | | | | | |
| | B Mitchell | 6 | 3 | 6 | | | | | | 4 | M Viola | 6 | 6 | | | | |
| WC | Masato Shiga | 5 | 2 | | | | | | | | Huang L-c | 3 | 0 | | | | |
| | A Kudryavtsev | 7 | 6 | | | A Kudryavtsev | 4 | 6$^3$ | | | | | | | | | |
| | Huang L-c | 6 | 7$^7$ | | | Huang L-c | 6 | 7$^7$ | | | | | | | | | |
| 8 | B Klein | 3 | 6$^2$ | | | | | | | | | | | | | | |

### 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 |
| 5 | H Moriya | 6 | 6 | | | | | | | | | | | | | | | |
| WC | Yoshihito Nishioka | 2 | 0 | | 5 | H Moriya | 7$^7$ | 3 | 6 | | | | | | | | | |
| WC | T Matsui | 2 | 6$^3$ | | PR | P Amritraj | 6$^3$ | 6 | 0 | | | | | | | | | |
| PR | P Amritraj | 6 | 7$^7$ | | | | | | | 5 | H Moriya | 3 | 2 | | | | | |
| | P Oswald | 2 | 4 | | | | | | | 3 | Y Sugita | 6 | 6 | | | | | |
| | J McGee | 6 | 6 | | | J McGee | 2 | 5 | | | | | | | | | | |
| Q | Yuuya Kibi | 1 | 2 | | 3 | Y Sugita | 6 | 7 | | | | | | | | | | |
| 3 | Y Sugita | 6 | 6 | | | | | | | | | | | | 3 | Y Sugita | 4 | 0 |
| 6 | T Chen | 4 | 6 | 4 | | | | | | | | | | | | M Bašić | 6 | 6 |
| Q | Shuichi Sekiguchi | 6 | 4 | 6 | Q | S Sekiguchi | 6$^2$ | 2 | | | | | | | | | | |
| | D King-Turner | 2 | 6 | 6$^5$ | | M Bašić | 7$^7$ | 6 | | | | | | | | | | |
| | M Bašić | 6 | 1 | 7$^7$ | | | | | | | M Bašić | 6 | 3 | 6 | | | | |
| Q | M Venus | 6$^5$ | 3 | | | | | | | 2 | R Ram | 4 | 6 | 1 | | | | |
| | C Rungkat | 7$^7$ | 6 | | | C Rungkat | 2 | 4 | | | | | | | | | | |
| WC | K Uchida | 6 | 3 | 6$^4$ | 2 | R Ram | 6 | 6 | | | | | | | | | | |
| 2 | R Ram | 4 | 6 | 7$^7$ | | | | | | | | | | | | | | |