Both Aichi and Nakajima offered aircraft to satisfy the Japanese Navy's requirement for a dive-bomber. The Aichi D3A1, known to the Americans as "Val", was ordered into production in December 1939 with an 840-hp Mitsubishi Kinsei 3 radial engine, but early production models were fitted with a 1,000-hp Mitsubishi Kinsei 43 and later production had the 1,070-hp Mitsubishi Kinsei 44 14-cylinder radial piston engine. The maximum speed at 9,845 feet was 239 mph and cruising speed was 183 mph. Range was 913 miles. Armament was two .303-in forward-firing Type 97 machine guns and one Type 92 .303-in on a trainable mount in the rear cockpit. It carried up to 816lb (370kg) of bombs. In the attack on Pearl Harbor 129 Vals were carried by the First Air Fleet. The 11th Attack Unit, 12th Attack Unit, 13th Attack Unit, 14th Attack Unit, 15th Attack Unit and 16th Attack Unit were equipped with these aircraft. A prototype with a 1,300-hp engine first flew in June 1942 and, as the major production version, the D3A2 Model 22 served for the duration of the war.
You can find out more about Japanese aircraft in the following Osprey books: