Taiwan named a former head of the Japanese defense forces as an adviser, according to officials in the Taiwanese government, a move that comes as the two governments deal with China’s increasing assertiveness.

Shigeru Iwasaki, the chief of staff of the Self-Defense Forces from 2012 through 2014, was named a consultant to Taiwan’s Cabinet, said the two officials who asked not to be identified discussing the sensitive issue.

The Cabinet usually doesn’t announce such appointments, one of the officials said.