Japanese judoka won four of the seven gold medals on offer on the opening day of the Paris Grand Slam judo tournament on Saturday.Wakana Koga, who took the women's 48-kilogram silver at the world championships in June, defeated France's Melanie Legoux Clement by ippon in the final of her weight class for Japan's first gold in the 50th edition of the International Judo Federation event.In the men's 66kg final, 19-year-old Ryoma Tanaka came out on top, beating fellow Japanese Taikoh Fujisaka in another ippon victory at AccorHotels Arena.Kenshi Harada won the men's 73kg title, and Haruka Funak…READ FULL ARTICLE