2018 Keio Challenger
The 2018 Keio Challenger was a professional tennis tournament played on hard courts. It was the thirteenth (ATP) and second (ITF) editions of the tournament and part of the 2018 ATP Challenger Tour and the 2018 ITF Women's Circuit. It took place in Yokohama, Japan between 26 February and 4 March 2018 for the men's edition and between 5 and 11 March 2018 for the women's.
| 2018 Keio Challenger | |
|---|---|
| Date | 26 February – 4 March (ATP) 5 – 11 March (ITF) | 
| Edition | 13th (ATP) 2nd (ITF) | 
| Category | ATP Challenger Tour ITF Women's Circuit | 
| Surface | Hard | 
| Location | Yokohama, Japan | 
| Champions | |
| Men's singles | |
|  Yasutaka Uchiyama | |
| Women's singles | |
|  Veronika Kudermetova | |
| Men's doubles | |
|  Tobias Kamke /  Tim Pütz | |
| Women's doubles | |
|  Laura Robson /  Fanny Stollár | |
Men's singles main-draw entrants
    
    Seeds
    
| Country | Player | Rank1 | Seed | 
|---|---|---|---|
| .svg.png.webp) AUS | Jordan Thompson | 95 | 1 | 
| .svg.png.webp) AUS | John Millman | 103 | 2 | 
|  TPE | Jason Jung | 153 | 3 | 
|  JPN | Go Soeda | 156 | 4 | 
|  FRA | Stéphane Robert | 158 | 5 | 
|  KOR | Kwon Soon-woo | 180 | 6 | 
|  JPN | Tatsuma Ito | 181 | 7 | 
|  KOR | Lee Duck-hee | 190 | 8 | 
- 1 Rankings are as of 19 February 2018.
Other entrants
    
The following players received wildcards into the singles main draw:
 Shinji Hazawa Shinji Hazawa
 Kaito Itsusaki Kaito Itsusaki
 Kaito Uesugi Kaito Uesugi
 Yosuke Watanuki Yosuke Watanuki
The following player received entry into the singles main draw as a special exempt:
The following players received entry from the qualifying draw:
 Chung Yun-seong Chung Yun-seong
 Hiroyasu Ehara Hiroyasu Ehara
 Hiroki Moriya Hiroki Moriya
 Jumpei Yamasaki Jumpei Yamasaki
The following player received entry as a lucky loser:
Women's singles main-draw entrants
    
    Seeds
    
| Country | Player | Rank1 | Seed | 
|---|---|---|---|
|  JPN | Eri Hozumi | 180 | 1 | 
|  JPN | Junri Namigata | 196 | 2 | 
|  JPN | Miharu Imanishi | 197 | 3 | 
|  ITA | Georgia Brescia | 202 | 4 | 
|  GBR | Laura Robson | 218 | 5 | 
|  TUR | Ayla Aksu | 226 | 6 | 
|  RUS | Veronika Kudermetova | 227 | 7 | 
|  CHN | Lu Jiajing | 232 | 8 | 
- 1 Rankings are as of 26 February 2018.
Other entrants
    
The following players received wildcards into the singles main draw:
The following players received entry from the qualifying draw:
Champions
    
    Men's singles
    
 Yasutaka Uchiyama def. Yasutaka Uchiyama def. Tatsuma Ito 2–6, 6–3, 6–4. Tatsuma Ito 2–6, 6–3, 6–4.
Women's singles
    
 Veronika Kudermetova def. Veronika Kudermetova def. Harriet Dart, 6–2, 6–4 Harriet Dart, 6–2, 6–4
Men's doubles
    
 Tobias Kamke / Tobias Kamke / Tim Pütz  def. Tim Pütz  def. Sanchai Ratiwatana / Sanchai Ratiwatana / Sonchat Ratiwatana 3–6, 7–5, [12–10]. Sonchat Ratiwatana 3–6, 7–5, [12–10].
Women's doubles
    
 Laura Robson / Laura Robson / Fanny Stollár def. Fanny Stollár def. Momoko Kobori / Momoko Kobori / Chihiro Muramatsu, 5–7, 6–2, [10–4] Chihiro Muramatsu, 5–7, 6–2, [10–4]

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