In 2014, Shimizu represented Japan at the Asian Games in Incheon, South Korea, and she won the gold medal in the women's kata event.

[7] At the 2016 World Karate Championships in Linz, Austria, Shimizu repeated her 2014 success by winning the gold medal in the women's kata event for the second time.

[3][13][14] Her success continued at the World Karate Championships held in Madrid, Spain where she won the silver medal in the women's individual kata event.

[11][15][16] At the 2019 Asian Karate Championships held in Tashkent, Uzbekistan, Shimizu won the gold medal in the women's individual kata event.

[19][20] She reached the final in the women's kata event, but lost the gold medal bout to Spain's Sandra Sánchez Jamie.