"Thunderbolt" 33 (j2m5): on May 20, 1944, the test flight was successful, equipped with "Mars" 26a engine, and the power system was greatly improved. On September 28 of the same year, in the test flight, his maximum speed reached 615 km / h, and it took only 9 minutes and 45 seconds to climb to 8000 meters, creating the highest Japanese fighter plane in the war. At that time, the B-29 had launched a large-scale air attack on Japan, and the navy was eager to produce the modified model. However, due to the evacuation of factories and other reasons, only more than 30 pieces were manufactured before and after. In addition, the improved stitches for refitting the 30 mm large caliber machine guns were also not implemented.