Defense Minister Shinjiro Koizumi and Philippine Defense Secretary Gilbert Teodoro (second from right) speak to soldiers during the Balikatan annual military exercises in Paoay, in the Philippines' Ilocos Norte province, on Wednesday. | AFP-JIJI From the sinking of a mock enemy ship to counterlanding drills in areas nearest Taiwan, Japan played an unprecedented role in the latest Balikatan exercises in the Philippines, highlighting Tokyo’s expanding role in the regional security architecture amid rising tensions. The three weeks of drills, which concluded Friday, marked the return of Japanese combat-capable forces to the Philippines for the first time since World War II — not as occupiers, but as close partners in one of the largest and most complex iterations of the annual exercises to date.…