Taiwan's army commander in chief, Gen. Hu Chen-pu, watched one of the Ground Self-Defense Force's major live-fire drills conducted Thursday in Shizuoka Prefecture, sources involved in Japan-Taiwan relations said.

China learned of the move beforehand and filed a prior protest over the "military exchange" between Japan and Taiwan, which it regards as a renegade province, but its objection ended up being effectively ignored, the sources said.

Although the Defense Agency did not officially invite Hu, invitees to the event can take their acquaintances with them and Hu is believed to have been among them.