The Watanabe K8W was a Japanese floatplane trainer designed and built by Watanabe for the Imperial Japanese Navy.
In 1937, the Imperial Japanese Navy drew up a specification for a 12-shi[a] primary floatplane trainer to replace its Yokosuka K4Y or Navy Type 90 Primary Seaplane Trainer.
The specification was issued to the established builders of aircraft for the Navy, Kawanishi and Watanabe and to the relative newcomer Nihon Hikoki (also known as "Nippi").
[2] The specification required use of the same Gasuden Jimpu radial engine used by the K4Y, and the three designs showed little changes from the aircraft they were to replace.
The trainee and instructor sat in individual open cockpits.