this, Japan's destroyer force was halved by the end of the war. The survivors were given to the Allies. Naval aviation Japan began the war with a highly competent naval air force designed around some of the best airplanes in the world: the A6M Zero was considered the best carrier aircraft of the beginning of the war, the Mitsubishi G3M bomber was remarkable for its range and speed, and the Kawanishi H8K was the world's best flying boat. The Japanese pilot corps at the beginning of the war were of high caliber as compared to their contemporaries around the world due to intense training and frontline experience in the Sino-Japanese War. The Navy also had a competent land-based tactical bombing force based around the Mitsubishi G3M and G4M bombers, which astonished the world by being the first planes to sink enemy capital ships underway, claiming battleship Prince of Wales and the battlecruiser Repulse. As the war progressed, the Allies found weaknesses in Japanese naval aviation. Though most Japanese aircraft were characterized by great operating range and agility, they had very little in the way of defensive armament and armor. As a result, the more numerous, heavily armed and armored American aircraft were able to develop techniques that nullified the advantages of the Japanese aircraft. The early carrier versus carrier naval battles in 1942 such as Coral Sea and Santa Cruz Island were tactical victories for the IJN but they suffered disproportionately high aircrew losses compared to the US Navy. The IJN did not have an efficient process for rapid training of aviators, as two years of training were usually considered necessary for a carrier flyer. Therefore, they were not able to effectively replace seasoned pilots lost through combat attrition following their initial successes in the Pacific campaign. The inexperience of IJN pilots who were trained in the later part of the war was especially evident during the Battle of the Philippine Sea, when their aircraft were shot down in droves by the American naval pilots in what the Americans later called the "Great Marianas Turkey Shoot". Following the Battle of Leyte Gulf, the Japanese Navy increasingly opted towards deploying aircraft in the kamikaze role. Although there were delays in engine development, several new competitive aircraft designs were developed during the war, but industrial weaknesses, lack of raw materials and disorganization due to Allied bombing raids hampered their mass-production. Towards the