Sasaki started internationally for the first time at the Nordic World Ski Championships in Oslo in 1982 . There he finished 56th place over 15 km, 53rd place over 30 km and 12th place with the relay. At the 1984 Winter Olympics in Sarajevo , he achieved 47th place over 15 km and 13th place with the relay. At the beginning of March 1986, he won the silver medal over 30 km freestyle and the gold medal over 15 km classic at the Winter Asian Games in Sapporo . The following year he ran at the Nordic World Ski Championships in Oberstdorf on 39th place over 15 km classic and 38th place over 50 km freestyle. His best results at the 1988 Winter Olympics in Calgary were 20th place over 30 km classic and 14th place with the relay. In the following year he won his first World Cup points at the Nordic World Ski Championships in Lahti with 15th place over 15 km classic, 13th place over 30 km classic and 11th place over 50 km freestyle. With the seventh place over 15 km freestyle he achieved his best individual result in the World Cup and at the end of the season with the 27th place in the overall World Cup his best overall result. In March 1990 he won at the Winter Asian Games in Sapporo over 15 km classic, over 30 km freestyle and with the relay the gold medal. At the Nordic World Ski Championships in 1991 in Val di Fiemme , he came in 27th place over 10 km classic, 14th place over 15 km freestyle and tenth place over 50 km freestyle and at the Olympic Winter Games 1992 in Albertville on 46 Place over 10 km classic, 40th place over 50 km freestyle and 30 km classic and 35th place in the pursuit. His best placings at the Nordic World Ski Championships in Falun in 1993 were 23rd place over 50 km freestyle and 11th place with the relay. His last international competitions were at the 1994 Winter Olympics in Lillehammer . There the 18th place in the pursuit and the 14th place with the relay were his best results.
Sasaki was three times the Japanese champion over 15 km (1984, 1985, 1986), five times over 15 km freestyle (1989, 1990, 1992-1994), four times over 15 km freestyle (1990, 1992-1994) and seven times over 30 km ( 1985, 1986, 1989, 1990, 1992–1994) and over 50 km (1985, 1986, 1988, 1989, 1990, 1992, 1994).
Participation in World Championships and Olympic Winter Games
Japan