YOKOSUKA, KANAGAWA PREF. - Journalists on Wednesday were given a guided tour of the Izumo — Japan’s largest flat-topped helicopter carrier — for the first time since the Defense Ministry revealed a controversial plan late last year to convert it so that it could handle fixed-wing aircraft — which critics and some opposition lawmakers say could make it capable of offensive operations. The pacifist postwar Constitution bans the possession of “attack aircraft carriers,” and calls for an exclusively defense-oriented posture. However, under a five-year defense build-up plan adopted in December, the 248-meter, 195,000-ton vessel will be undergoing a major remodeling...