Under the Japanese Trademark Law, similarity between trademarks in question and prior registered trademarks is evaluated using the "likelihood of confusion" standard.
Under this standard, due account is to be taken as regards designated goods or services with respect to which both trademarks are used as well as any identity or similarity between the trademarks and prior registered trademarks themselves. "Hyozan case" is a leading case on this issue decided by the Supreme Court (Minshu 22, No. 2, 399).