Xysticus croceus

Xysticus croceus is a crab spider in the genus Xysticus found in Nepal, Bhutan, China, Korea, Taiwan, and in Japan, where it is called "yami-iro kani-gumo". It is about 7 mm long

It looks in grass and fallen leaves for prey to eat. It hides under stones in the winter, and is often seen in spring and early summer.