Is the casualties of Japanese in mainland china true? They actually reached around 600000?

My grandpa told me 2 Japanese soldiers could control the whole county when they first invaded my state, where I was born they literally just came and shot 2 Chinese soldiers guarding the dock and hung around for few days then left, no resistance. old people in the villages told me they went hiding in mountains, old people in my county said most of japanese soldiers just stayed for few days. I was born in Zhejiang, Wenzhou.