Mitsubishi A6M 'Zero', part four, early variants part one

As the 'Zero' was the backbone of the Imperial Japanese Navy Air Service's (IJNAS) fighter force, many variants were manufactured. Some of those are the following:

• A6M1 Type 0 12-shi: The first two A6M prototypes were completed in March 1939. They were powered by a 780 hp Mitsubishi Zusei 13 radial engine driving a two-bladed propeller. They flew for the first time on 1st April and passed testing in a remarkably short period of time. In September that year it had already been accepted by the IJNAS for testing as the 'A6M1 Type 0 Carrier Fighter' with the only change of switching to a three-bladed propeller to fix a vibration problem.
  Just two aircraft were made at Mitsubishi's factory in Nagoya, Japan.
• A6M2a Type 0 Model 11: As the IJNAS was testing the first two prototypes, they suggested the third prototype which was still under fabrication, to be fitted with the 940 hp Nakajima Sakae 12 radial engine. As Mitsubishi had their own engine of this kind under manufacturing as the Mitsubishi Kinsei, and considering the rivalry between Nakajima and Mitsubishi, they were reluctant to use it. Anyway, when the first A6M2 was completed in January 1940, thanks to the Sakae's extra power, it pushed the performance of the Zero well past beyond its original specifications.
  As the reports of this new variant were so promising, the IJNAS had a first batch of 15 machines built and shipped to China before they had completed testing. They arrived in Manchuria in July 1940 and saw combat for the first time over the province of Chungking in August. There, they showed their absolute superiority over the Soviet-built Polikarpov I-16 and I-153 that were a problem for the previous A5M. In a single encounter, a formation of 13 Zeroes shot down 27 I-15s and I-16s in less than three minutes without a single loss for themselves. After listening to those reports, the IJNAS ordered the manufacturing of the A6M2 as the A6M2a Type 0 Carrier Figher Model 11. Some reports of the Zero's performance were filtered to US officials but they were dismissed by most of them who thought it was impossible for the Japanese to build such an aircraft.
  A total of 64 machines were manufactured at Mitsubishi's factory in Nagoya between May and November 1940.
• A6M2b Type 0 Model 21: After the 64th aircraft of the previous model was built, the design was changed to allow folding wingtips to be introduced in order to improve carrier effectiveness. This resulting model, called 'A6M2b Type 0 Carrier Fighter Model 21' became one of the most produced fighters during the early part of the World War 2. It was also fitted with a 520 L (140 US Gal) wing tank which improved its range even further. Production lines were switched towards the Model 21 and, in total, 740 machines were completed by Mitsubishi at Nagoya and 800 of them by Nakajima in Koizumi, Japan, making it a total of 1540 machines manufactured since November 1940 and November 1941 for Nakajima's ones. Two further sub-variants were built: The Nakajima A6M2-N (which will be the subject of its own post) and the A6M2-K.
• A6M2-K: This variant was a two-seat trainer conversion. A total of 508 machines were completed as the A6M2 was being replaced in frontline service by the A6M3. An unknown number of them were fitted with towing equipment and some of them were used in kamikaze attacks. A total of 508 machines were completed in a production period ranging from November 1943 until August 1945.
  They were manufactured by the 21st Naval Aviation Workshop (where it was also designed and 236 of them were completed) at the city of Omura, Japan and the remaining 272 of them were completed by Hitachi at Tachikawa, Japan from May 1944 until August 1945. Something similar was made with the more advanced A6M5 version, but just like the A6M2-N, we will write about it later.
  Apparently there was a makeshift courier two-seater aircraft. At least one machine was modified to make it two-seater as the personal aircraft of a top Japanese Commander in the South Pacific region in 1944. As we could find just one black & white photo of this aircraft, the drawing should be considered as semi-speculative.

Sources:

1. https://en.wikipedia.org/wiki/Mitsubishi_A6M_Zero

2. https://www.valka.cz/topic/view/32999/Micubisi-A6M1 (translated)

3. https://www.valka.cz/topic/view/116760/Micubisi-A6M2-11 (translated)

4. https://www.valka.cz/topic/view/1277/Micubisi-A6M2-21 (translated)

5. https://www.valka.cz/topic/view/27351/Micubisi-A6M2-K (translated)

6. http://www.j-aircraft.com/a6mresearch/zerotrnr.htm

7. AJ-Press - Monografie Lotnicze 7 - Mitsubishi A-6M Zero (translated)

8. Salamander Books - The Complete Book of fighters

9. Signal Squadron - Aircraft In action 59 - Mitsubishi A6M Zero in Action