TOKYO — Dozens of U.S. Navy and Japan Maritime Self Defense Force warships gathered in the East China Sea last week as part of a major war exercise — but not that you’d know it. Exercise Keen Sword is held every other year to test inter-operability of U.S. and Japanese air, land and sea forces. But media coverage was severely restricted this year and a large-scale amphibious assault exercise was canceled. The reason: to avoid worsening the territorial dispute over Japan’s Senkaku Islands, which China also claims (and calls Diaoyu). The U.S-Japanese fleet, one of the largest ever assembled, was within a days’ cruise of the islands. The 12-day Keen Sword exercise concluded Nov. 17.