# 2018 Keio Challenger – Men's singles

Yūichi Sugita was the defending champion but chose not to defend his title.
Yasutaka Uchiyama won the title after defeating Tatsuma Ito 2–6, 6–3, 6–4 in the final.

## Seeds

* Jordan Thompson (semifinals)
* John Millman (second round, withdrew)
* Jason Jung (second round)
* Go Soeda (quarterfinals)
* Stéphane Robert (quarterfinals)
* Kwon Soon-woo (first round)
* Tatsuma Ito (final)
* Lee Duck-hee (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

| Semifinals | Semifinals | Semifinals | Semifinals | Final | Final | Final | Final | Final |
| 1 | Jordan Thompson | 4 | 5 | | | | | |
| | Yasutaka Uchiyama | 6 | 7 | | | | | |
| | Yasutaka Uchiyama | 6 | 7 | | Yasutaka Uchiyama | 2 | 6 | 6 |
| | | | | 7 | Tatsuma Ito | 6 | 3 | 4 |
| | Cem İlkel | | | 7 | Tatsuma Ito | 6 | 3 | 4 |
| 7 | Tatsuma Ito | w/o | | | | | | |

### Top half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 1 | J Thompson | 2 | 6 | 6 | | | | | | | | | | | | | |
| | P Gunneswaran | 6 | 4 | 3 | 1 | J Thompson | 6 | 6 | | | | | | | | | |
| Q | Hiroyasu Ehara | 7$^{10}$ | 6$^1$ | 6 | Q | H Ehara | 4 | 2 | | | | | | | | | |
| | A Whittington | 6$^8$ | 7$^7$ | 4 | | | | | 1 | J Thompson | 6 | 4 | 6 | | | | |
| LL | D Nguyen | 6 | 6 | | | | | | 5 | S Robert | 3 | 6 | 2 | | | | |
| WC | Yo Watanuki | 2 | 4 | | LL | D Nguyen | 5 | 0 | | | | | | | | | |
| Q | Jumpei Yamasaki | 6 | 1 | 3 | 5 | S Robert | 7 | 6 | | | | | | | | | |
| 5 | S Robert | 3 | 6 | 6 | | | | | | | | | | 1 | J Thompson | 4 | 5 |
| 4 | G Soeda | 6 | 6 | | | | | | | | | | | | Y Uchiyama | 6 | 7 |
| WC | Kaito Itsusaki | 0 | 2 | | 4 | G Soeda | 7$^7$ | 6 | | | | | | | | | |
| | D Wu | 6 | 7$^7$ | | | D Wu | 6$^5$ | 3 | | | | | | | | | |
| | Ze Zhang | 4 | 6$^5$ | | | | | | 4 | G Soeda | 6 | 6$^0$ | 3 | | | | |
| | Y Uchiyama | 6 | 3 | 6 | | | | | | Y Uchiyama | 4 | 7$^7$ | 6 | | | | |
| | H Hurkacz | 4 | 6 | 4 | | Y Uchiyama | 6 | 7 | | | | | | | | | |
| WC | S Hazawa | 6 | 4 | 7$^7$ | WC | S Hazawa | 3 | 5 | | | | | | | | | |
| 6 | S-w Kwon | 3 | 6 | 6$^5$ | | | | | | | | | | | | | |

### 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 | Semifinals | Semifinals | Semifinals |
| 8 | D-h Lee | 4 | 6 | 6 | | | | | | | | | | | | |
| | T Pütz | 6 | 4 | 3 | 8 | D-h Lee | 2 | 6 | 6$^5$ | | | | | | | |
| SE | B Ellis | 3 | 4 | | | C İlkel | 6 | 2 | 7$^7$ | | | | | | | |
| | C İlkel | 6 | 6 | | | | | | | | C İlkel | 7$^7$ | 6 | | | |
| | M Donati | 7$^{11}$ | 2 | 5 | | | | | | | T Kamke | 6$^3$ | 2 | | | |
| | T Kamke | 6$^9$ | 6 | 7 | | T Kamke | 6 | 6 | | | | | | | | |
| Q | Y-s Chung | 2 | 7$^8$ | 4 | 3 | J Jung | 4 | 2 | | | | | | | | |
| 3 | J Jung | 6 | 6$^6$ | 6 | | | | | | | | | | | C İlkel | |
| 7 | T Ito | 6 | 6 | | | | | | | | | | | 7 | T Ito | w/o |
| WC | K Uesugi | 2 | 3 | | 7 | T Ito | 3 | 6 | 7$^7$ | | | | | | | |
| | J Kubler | 6 | 1 | 6 | | J Kubler | 6 | 3 | 6$^3$ | | | | | | | |
| | E Leshem | 3 | 6 | 3 | | | | | | 7 | T Ito | 6 | 6 | | | |
| | K Kravchuk | 0 | 2 | | | | | | | Q | H Moriya | 3 | 3 | | | |
| Q | H Moriya | 6 | 6 | | Q | H Moriya | w/o | | | | | | | | | |
| | M Purcell | 3 | 6$^7$ | | 2 | J Millman | | | | | | | | | | |
| 2 | J Millman | 6 | 7$^9$ | | | | | | | | | | | | | |