Shnaider, of Russia, fired three aces and won 26 of 32 points on her first serve to dispatch the Japanese native in 77 minutes.
No. 3 seed Leylah Fernandez of Canada took advantage of seven double faults to coast to a 6-2, 6-2 win over Great Britain's Heather Watson.
No. 8 Cristina Bucsa of Spain seized a 6-3, 6-3 triumph over local favorite Hong Yi Cody Wong, while No. 7 Varvara Gracheva of France overcame a first-set stumble in a 2-6, 7-5, 6-2 victory over Tatiana Prozorova of Russia.
Jiangxi Open
Second-seeded Rebecca Sramkova breezed to a 6-1, 6-1 victory over local favorite Shuai Zhang in an opening-round match in Jiujiang, China.
Sramkova, of Slovakia, fired nine aces and took advantage of six double faults to dismiss Zhang in 48 minutes.
Unseeded German Laura Siegemund upended third-seeded Moyuka Uchijima 7-5, 6-3 and Thailand's Mananchaya knocked out No. 7 seed Lucia Bronzetti of Italy 6-4, 4-6, 6-2.