WWII Japanese postcard?

I have a set of four; all the pictures are different and the backs of the cards (3"x 5") are covered with Japanese writing. I think that the one pictured is of Tokugawa Ieyasu and gives some history of him. I looked him up and he is the warrior, statesman and founder of the Tokugawa dynasty.

Can anyone tell what the card is, why it would have been made and when? What I think I know is that the cards date back to WWII, but I may be completely wrong. I am under the belief that my late father brought them back with him when he returned from being stationed in Japan during WWII. I'm very curious, as I have not seen anything like them online.

Thanks in advance for any help you can give me!

Jeanne C.