it is held since 1976 and is part of the World Rugby Sevens Series since 2000. Other notable rugby sevens tournaments in Asia have been the Dubai Sevens, Japan Sevens, Singapore Sevens, Malaysia Sevens and China Sevens. Japan hosted the 2019 Rugby World Cup. The Top League is Japan's premier rugby club competition, founded in 2003. In 2016, the Sunwolves joined the Southern Hemisphere-based Super Rugby. The team is based in Tokyo but also plays home games in Singapore. Tennis The most successful Asian countries in tennis have been India, China, Japan and Taiwan. In men's singles, Kei Nishikori was finalist at the 2014 US Open and two ATP Masters 1000 tournaments, whereas Vijay Amritraj reached quarter-finals at four Grand Slams and was semifinalist at the 1982 WCT Finals. In men's doubles, Leander Paes of India won eight Grand Slams tournaments and Mahesh Bhupathi won four Grand Slams tournaments and in mixed double Paes won 10 and Bhupathi won 8 grand slams. Leander Paes won total of 18 grand slams which is the highest by an Asian tennis player and also he is among the very few to complete career slam in both men's doubles and mixed doubles. Rohan Bopanna won his first mixed doubles grand slam title at the 2017 French Open. So far only Indian men are successful in winning grand slams and also the most successful Asian team at the Davis Cup having reached the finals on three occasions. Sania Mirza is the most successful female tennis player having won 6 grand slams 3 each in women's doubles and mixed doubles. Sania Mirza was ranked World No.1 in women's doubles for 91 consecutive weeks. In women's singles, Li Na won two Grand Slam titles at the 2011 French Open and 2014 Australian Open. Naomi Osaka of Japan became the second women's singles player to win Grand slam winning 2018 US Open and 2019 Australian Open, whereas Kimiko Date-Krumm won four Japan Open titles was semifinalist at three Grand Slam tournaments. Notable women's doubles players include, Ai Sugiyama, Hsieh Su-wei, Peng Shuai and Zheng Jie. Volleyball In men's volleyball, the Japan national team has won three Olympic medals, including a gold medal in 1972. Also, the team was third at the 1970 and 1974 World Championship, and second at the 1969 and 1977 World Cup. Japan has been less successful in the World League era. Meanwhile, South Korea