 By 1912, disappearing guns were declared obsolete in the British Army, with only a few other countries, particularly the United States, still producing them up to World War I and retaining them in service until replaced by casemated batteries in World War II.The only major campaign in which US disappearing guns played a part was the Japanese invasion of the Philippines, which began shortly after the attack on Pearl Harbor on 7 December 1941 and ended with the surrender of US forces on 6 May 1942.The disappearing guns were the least useful of the coast defense assets, as they were positioned to defend against warships entering Manila Bay and Subic Bay and in most cases could not engage Japanese forces due to limited traverse.