Mitsubishi A5M, part three

The most competitive adversary that the A5M faced was the Soviet Polikarpov I-16 which was a fast and heavily armed fighter that was flown both by Chinese Nationalist pilots and Soviet volunteers. The aerial battles that took place on 18th February and 29th April 1938 were the largest ones ever seen up to that time.
The battle of 29th April confronted 31 Polikarpov I-16s and 36 Polikarpov I-15bis (making it a total of 67 of them) versus 18 Mitsubishi G3M escorted by 27 A5Ms. Victory was claimed by each side, as the Sino-Soviet side claimed 11 fighters and 10 bombers (making it a total of 21) with a total of 50 airmen killed and two captured at a cost of 12 aircraft lost and 5 pilots killed. On the other hand, the Japanese claimed they only lost two G3Ms and other two A5Ms with more than 40 Chinese aircrafts shot down.
The Mitsubishi A5M2b was a version with an enclosed NACA cowling. It was manufactured from October 1937 until 1938 by Mitsubishi Heavy Industries, in Nagoya, Japan with 108 of them made and the 21st Naval Aviation Workshop manufactured 16 of them in 1939. A total of 124 of them were manufactured. It was powered by a single Nakajima Kotobuki 3, nine-cylinder air-cooled single-row radial which delivered a power of 631hp for take-off and 705hp at 9186ft high (2800m).
It was armed with two 0.303in (7,7mm) Type 89 machine guns placed at the nose and could carry a small bomb payload of 60kg (132lb).
This variant was barely used as the next main variant, the A5M4, was already pushing for being Imperial Japanese Navy Air Service's main fighter.

Sources:
1. https://en.wikipedia.org/wiki/Mitsubishi_A5M
2. https://forum.valka.cz/topic/view/28830
3. Salamander Books - The Complete Book of Fighters