# 2023 Kobe Challenger – Singles

Yosuke Watanuki was the defending champion but chose not to defend his title.
Duje Ajduković won the title after defeating Sho Shimabukuro 6–4, 6–2 in the final.

## Seeds

* Jurij Rodionov (quarterfinals)
* Shintaro Mochizuki (quarterfinals)
* Luca Nardi (semifinals)
* Benjamin Hassan (second round)
* Sho Shimabukuro (final)
* Marc Polmans (quarterfinals)
* Bu Yunchaokete (withdrew)
* Zdeněk Kolář (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 | Semifinals | Final | Final | Final | Final |
| | Duje Ajduković | 7 | 5 | 6 | | | | |
| | Wu Tung-lin | 5 | 7 | 3 | | | | |
| | Wu Tung-lin | 5 | 7 | 3 | | Duje Ajduković | 6 | 6 |
| | | | | | 5 | Sho Shimabukuro | 4 | 2 |
| 3 | Luca Nardi | 2 | 2 | | 5 | Sho Shimabukuro | 4 | 2 |
| 5 | Sho Shimabukuro | 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 | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 1 | J Rodionov | 7$^7$ | 6 | | | | | | | | | | | | | | | |
| Q | Y Uchiyama | 6$^5$ | 4 | | 1 | J Rodionov | 6 | 2 | 6 | | | | | | | | | |
| WC | T Ito | 6$^6$ | 3 | | | Y Shimizu | 1 | 6 | 1 | | | | | | | | | |
| | Y Shimizu | 7$^8$ | 6 | | | | | | | 1 | J Rodionov | 6$^5$ | 6 | 1 | | | | |
| | D Ajduković | 6 | 6 | | | | | | | | D Ajduković | 7$^7$ | 4 | 6 | | | | |
| | M Efstathiou | 2 | 2 | | | D Ajduković | 6 | 5 | 6 | | | | | | | | | |
| | Y-h Hsu | 4 | 3 | | LL | R Noguchi | 0 | 7 | 3 | | | | | | | | | |
| LL | R Noguchi | 6 | 6 | | | | | | | | | | | | D Ajduković | 7 | 5 | 6 |
| 4 | B Hassan | 0 | 6 | 6 | | | | | | | | | | | T-l Wu | 5 | 7 | 3 |
| | J McCabe | 6 | 3 | 2 | 4 | B Hassan | 3 | 4 | | | | | | | | | | |
| | D Sweeny | 3 | 6$^2$ | | | T-l Wu | 6 | 6 | | | | | | | | | | |
| | T-l Wu | 6 | 7$^7$ | | | | | | | | T-l Wu | 6 | 6 | | | | | |
| WC | Renta Tokuda | 6 | 1 | 2 | | | | | | | J Jung | 4 | 3 | | | | | |
| Q | Y-s Chung | 4 | 6 | 6 | Q | Y-s Chung | 7$^7$ | 3 | 1$^r$ | | | | | | | | | |
| | J Jung | 6 | 7$^7$ | | | J Jung | 6$^2$ | 6 | 4 | | | | | | | | | |
| 8 | Z Kolář | 4 | 6$^4$ | | | | | | | | | | | | | | | |

### 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 | Semifinals |
| 6 | M Polmans | 6 | 7 | | | | | | | | | | | | | | |
| Q | Andrew Fenty | 2 | 5 | | 6 | M Polmans | 6 | 7$^7$ | | | | | | | | | |
| | A Martin | 4 | 4 | | | G Blancaneaux | 4 | 6$^3$ | | | | | | | | | |
| | G Blancaneaux | 6 | 6 | | | | | | | 6 | M Polmans | 2 | 4 | | | | |
| Q | A Holmgren | 6 | 6 | | | | | | | 3 | L Nardi | 6 | 6 | | | | |
| | M Echargui | 4 | 3 | | Q | A Holmgren | 3 | 6 | 5 | | | | | | | | |
| WC | T Ichikawa | 5 | 2 | | 3 | L Nardi | 6 | 3 | 7 | | | | | | | | |
| 3 | L Nardi | 7 | 6 | | | | | | | | | | | 3 | L Nardi | 2 | 2 |
| 5 | S Shimabukuro | 6 | 7$^7$ | | | | | | | | | | | 5 | S Shimabukuro | 6 | 6 |
| | K Uchida | 1 | 6$^5$ | | 5 | S Shimabukuro | 6 | 7$^7$ | | | | | | | | | |
| Alt | O Jasika | 3 | 1 | | | S-c Hong | 4 | 6$^4$ | | | | | | | | | |
| | S-c Hong | 6 | 6 | | | | | | | 5 | S Shimabukuro | 6 | 6 | | | | |
| Q | K Ivanovski | 1 | 0$^r$ | | | | | | | 2 | S Mochizuki | 3 | 3 | | | | |
| LL | Y Bai | 6 | 4 | | LL | Y Bai | 3 | 2 | | | | | | | | | |
| Q | G Fonio | 6 | 2 | 3 | 2 | S Mochizuki | 6 | 6 | | | | | | | | | |
| 2 | S Mochizuki | 4 | 6 | 6 | | | | | | | | | | | | | |