# 2019 Keio Challenger – Men's singles

Yasutaka Uchiyama was the defending champion but chose not to defend his title.
Kwon Soon-woo won the title after defeating Oscar Otte 7–6$^{(7–4)}$, 6–3 in the final.

## Seeds

All seeds receive a bye into the second round.
* Tatsuma Ito (third round)
* Oscar Otte (final)
* Yūichi Sugita (semifinals)
* Hiroki Moriya (second round)
* Mats Moraing (third round)
* Jurij Rodionov (third round)
* Go Soeda (third round)
* Dudi Sela (quarterfinals)
* Blaž Rola (third round)
* Gianluca Mager (quarterfinals)
* Kwon Soon-woo (champion)
* Pedro Cachin (second round)
* Guilherme Clezar (second round)
* Filip Peliwo (third round)
* Viktor Troicki (second round)
* Enzo Couacaud (second 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

| Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals | Final | Final | Final | Final |
| | Lee Duck-hee | 1 | 0 | | | | | | | | | |
| 11 | Kwon Soon-woo | 6 | 6 | | | | | | | | | |
| 11 | Kwon Soon-woo | 6 | 6 | | 11 | Kwon Soon-woo | 6 | 6 | | | | |
| | | | | | 3 | Yūichi Sugita | 3 | 2 | | | | |
| 3 | Yūichi Sugita | 2 | 6 | 7 | 3 | Yūichi Sugita | 3 | 2 | | | | |
| 8 | Dudi Sela | 6 | 4 | 5 | | | | | | | | |
| 8 | Dudi Sela | 6 | 4 | 5 | | | | | 11 | Kwon Soon-woo | 7$^7$ | 6 |
| | | | | | | | | | 2 | Oscar Otte | 6$^4$ | 3 |
| | Yang Tsung-hua | 5 | 6$^4$ | | | | | | | | | | 2 | Oscar Otte | 6$^4$ | 3 |
| | Andrew Harris | 7 | 7$^7$ | | | | | | | | | |
| | Andrew Harris | 7 | 7$^7$ | | | Andrew Harris | 3 | 4 | | | | |
| | | | | | 2 | Oscar Otte | 6 | 6 | | | | |
| 10 | Gianluca Mager | 2 | 4 | | 2 | Oscar Otte | 6 | 6 | | | | |
| 2 | Oscar Otte | 6 | 6 | | | | | | | | | |

### Top half
#### Section 1

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Third round | Third round | Third round | Third round | Third round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals |
| | | | | | 1 | T Ito | 6 | 7 | | | | | | | | | |
| | Y Takahashi | 5 | 7 | 2 | ITF | M Echargui | 0 | 5 | | | | | | | | | |
| ITF | M Echargui | 7 | 5 | 6 | | | | | 1 | T Ito | 3 | 6 | 6$^7$ | | | | |
| | D-h Lee | 6 | 6 | | | | | | | D-h Lee | 6 | 4 | 7$^9$ | | | | |
| | Xia Zihao | 0 | 3 | | | D-h Lee | 6 | 6 | | | | | | | | | |
| | | | | | 16 | E Couacaud | 0 | 2 | | | | | | | | | |
| | | | | | | | | | | | | | | | D-h Lee | 1 | 0 |
| | | | | | | | | | | | | | | 11 | S-w Kwon | 6 | 6 |
| | | | | | 11 | S-w Kwon | 6 | 6 | | | | | | | | | |
| | Renta Tokuda | 5 | 2 | | WC | M Imamura | 2 | 2 | | | | | | | | | |
| WC | M Imamura | 7 | 6 | | | | | | 11 | S-w Kwon | 6 | 6 | | | | | |
| WC | S Hazawa | 6$^2$ | 4 | | | | | | 5 | M Moraing | 2 | 4 | | | | | |
| | TK Wang | 7$^7$ | 6 | | | TK Wang | 6$^8$ | 2 | | | | | | | | | |
| | | | | | 5 | M Moraing | 7$^{10}$ | 6 | | | | | | | | | |

#### Section 2

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Third round | Third round | Third round | Third round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals |
| | | | | | 3 | Y Sugita | 2 | 6 | 7 | | | | | | | | | |
| | B Ellis | 6 | 5 | 5 | PR | D Nguyen | 6 | 4 | 5 | | | | | | | | | |
| PR | D Nguyen | 3 | 7 | 7 | | | | | | 3 | Y Sugita | 6 | 6 | | | | | |
| | G Oliveira | 3 | 6$^5$ | | | | | | | 14 | F Peliwo | 4 | 2 | | | | | |
| ITF | I Gakhov | 6 | 7$^7$ | | ITF | I Gakhov | 2 | 4 | | | | | | | | | | |
| | | | | | 14 | F Peliwo | 6 | 6 | | | | | | | | | | |
| | | | | | | | | | | | | | | 3 | Y Sugita | 2 | 6 | 7 |
| | | | | | | | | | | | | | | 8 | D Sela | 6 | 4 | 5 |
| | | | | | 9 | B Rola | 7$^7$ | 6 | | | | | | | | | | |
| | K Uchida | 6 | 6 | | | K Uchida | 6$^3$ | 4 | | | | | | | | | | |
| | Roy Smith | 3 | 3 | | | | | | | 9 | B Rola | 3 | 1 | | | | | |
| | L Saville | 2 | 6 | 6 | | | | | | 8 | D Sela | 6 | 6 | | | | | |
| WC | K Uesugi | 6 | 4 | 2 | | L Saville | 2 | 0 | | | | | | | | | | |
| | | | | | 8 | D Sela | 6 | 6 | | | | | | | | | | |

### Bottom half
#### Section 3

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Third round | Third round | Third round | Third round | Third round | Quarterfinals | Quarterfinals | Quarterfinals |
| | | | | | 6 | J Rodionov | 7$^9$ | 0 | 6 | | | | | | | | |
| LL | Shintaro Imai | 2 | 3 | | ITF | D Pérez Sanz | 6$^7$ | 6 | 4 | | | | | | | | |
| ITF | D Pérez Sanz | 6 | 6 | | | | | | | 6 | J Rodionov | 4 | 4 | | | | |
| | Y-s Chung | 4 | 3 | | | | | | | | T-h Yang | 6 | 6 | | | | |
| | T-h Yang | 6 | 6 | | | T-h Yang | 6 | 6 | | | | | | | | | |
| | | | | | 12 | P Cachin | 4 | 4 | | | | | | | | | |
| | | | | | | | | | | | | | | | T-h Yang | 5 | 6$^4$ |
| | | | | | | | | | | | | | | | A Harris | 7 | 7$^7$ |
| | | | | | 13 | G Clezar | 6 | 2 | 6$^4$ | | | | | | | | |
| | D Wu | 4 | 6 | 2 | | G Elias | 0 | 6 | 7$^7$ | | | | | | | | |
| | G Elias | 6 | 3 | 6 | | | | | | | G Elias | 4 | 7 | 4 | | | |
| | A Harris | 6 | 6 | | | | | | | | A Harris | 6 | 5 | 6 | | | |
| WC | Sung Yo-han | 1 | 2 | | | A Harris | 6 | 6 | | | | | | | | | |
| | | | | | 4 | H Moriya | 3 | 3 | | | | | | | | | |

#### Section 4

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Third round | Third round | Third round | Third round | Third round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals |
| | | | | | 7 | G Soeda | 6 | 6 | | | | | | | | | |
| Q | Kim Cheong-eui | 6 | 6 | | Q | C-e Kim | 1 | 4 | | | | | | | | | |
| WC | Naoto Kai | 1 | 3 | | | | | | 7 | G Soeda | 6 | 5 | 5 | | | | |
| Q | C-h Tseng | 6 | 3 | 6 | | | | | 10 | G Mager | 3 | 7 | 7 | | | | |
| ITF | S Mansouri | 4 | 6 | 3 | Q | C-h Tseng | 6$^3$ | 6$^5$ | | | | | | | | | |
| | | | | | 10 | G Mager | 7$^7$ | 7$^7$ | | | | | | | | | |
| | | | | | | | | | | | | | | 10 | G Mager | 2 | 4 |
| | | | | | | | | | | | | | | 2 | O Otte | 6 | 6 |
| | | | | | 15 | V Troicki | 5 | 6$^5$ | | | | | | | | | |
| | M Purcell | 6 | 6 | | | M Purcell | 7 | 7$^7$ | | | | | | | | | |
| | K King | 2 | 2 | | | | | | | M Purcell | 6 | 5 | 4 | | | | |
| | Y Bai | 6 | 0 | 7 | | | | | 2 | O Otte | 1 | 7 | 6 | | | | |
| | Makoto Ochi | 2 | 6 | 5 | | Y Bai | 3 | 2 | | | | | | | | | |
| | | | | | 2 | O Otte | 6 | 6 | | | | | | | | | |