# 2003 AIG Japan Open Tennis Championships – Women's singles

Jill Craybas was the defending champion, but lost in quarterfinals to Arantxa Parra Santonja.
Maria Sharapova won the title by defeating Anikó Kapros 2–6, 6–2, 7–6$^{(7–5)}$ in the final.

## Seeds

The first two seeds received a bye into the second round.
* Ai Sugiyama (quarterfinals)
* Tamarine Tanasugarn (second round)
* Katarina Srebotnik (second round)
* Shinobu Asagoe (second round)
* Maria Sharapova (champion)
* Ashley Harkleroad (second round)
* Saori Obata (first round)
* Emmanuelle Gagliardi (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 |
| | Anikó Kapros | 6 | 6 | | | | | |
| | Arantxa Parra Santonja | 1 | 2 | | | | | |
| | Arantxa Parra Santonja | 1 | 2 | | Anikó Kapros | 6 | 2 | 6$^5$ |
| | | | | 5 | Maria Sharapova | 2 | 6 | 7$^7$ |
| 5 | Maria Sharapova | 6 | 7 | 5 | Maria Sharapova | 2 | 6 | 7$^7$ |
| | Zheng Jie | 3 | 5 | | | | | |

### 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 |
| | | | | | 1 | A Sugiyama | 6 | 3 | 7$^7$ | | | | | | | | |
| | A Widjaja | 4 | 5 | | | Y Yoshida | 3 | 6 | 6$^0$ | | | | | | | | |
| | Y Yoshida | 6 | 7 | | | | | | | 1 | A Sugiyama | 4 | 2$^r$ | | | | |
| Q | T Sun | 4 | 2 | | | | | | | | A Kapros | 6 | 3 | | | | |
| | A Kapros | 6 | 6 | | | A Kapros | 6 | 6 | | | | | | | | | |
| Q | A Spears | 1 | 6 | 4 | 8 | E Gagliardi | 0 | 2 | | | | | | | | | |
| 8 | E Gagliardi | 6 | 2 | 6 | | | | | | | | | | | A Kapros | 6 | 6 |
| 4 | S Asagoe | 6 | 6 | | | | | | | | | | | | A Parra Santonja | 1 | 2 |
| Q | T Li | 1 | 1 | | 4 | S Asagoe | 7 | 4 | 3 | | | | | | | | |
| | An Serra Zanetti | 1 | 2 | | | A Parra Santonja | 5 | 6 | 6 | | | | | | | | |
| | A Parra Santonja | 6 | 6 | | | | | | | | A Parra Santonja | 3 | 6 | 6 | | | |
| | A Cargill | 3 | 2 | | | | | | | | J Craybas | 6 | 4 | 2 | | | |
| WC | R Fujiwara | 6 | 6 | | WC | R Fujiwara | 6 | 4 | 2 | | | | | | | | |
| | J Craybas | 6 | 6 | | | J Craybas | 4 | 6 | 6 | | | | | | | | |
| 7 | S Obata | 4 | 2 | | | | | | | | | | | | | | |

### Bottom half

| 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 |
| 5 | M Sharapova | 6 | 6 | | | | | | | | | | | | | |
| LL | J-h Kim | 2 | 0 | 5 | M Sharapova | 6 | 6 | | | | | | | | | |
| | A Morigami | 6 | 6 | | A Morigami | 1 | 3 | | | | | | | | | |
| | M Kirilenko | 1 | 2 | | | | | | 5 | M Sharapova | 7 | 7$^7$ | | | | |
| | M Suchá | 1 | 5 | | | | | | | C Schaul | 5 | 6$^1$ | | | | |
| | C Schaul | 6 | 7 | | C Schaul | 6 | 2 | 7$^7$ | | | | | | | | |
| | E Dominikovic | 3 | 3 | 3 | K Srebotnik | 3 | 6 | 6$^5$ | | | | | | | | |
| 3 | K Srebotnik | 6 | 6 | | | | | | | | | | 5 | M Sharapova | 6 | 7 |
| 6 | A Harkleroad | 6 | 6 | | | | | | | | | | | J Zheng | 3 | 5 |
| WC | M Ozaki | 0 | 0 | 6 | A Harkleroad | 6$^5$ | 4 | | | | | | | | | |
| LL | Z Yan | 6 | 6 | LL | Z Yan | 7$^7$ | 6 | | | | | | | | | |
| Q | M Saeki | 2 | 4 | | | | | | LL | Z Yan | 6$^3$ | 3 | | | | |
| | J Zheng | 6 | 7 | | | | | | | J Zheng | 7$^7$ | 6 | | | | |
| | S Talaja | 4 | 5 | | J Zheng | 1 | 6 | 6 | | | | | | | | |
| | | | | 2 | T Tanasugarn | 6 | 2 | 4 | | | | | | | | |