Japanese Samurai armor (uniform). This one was used in the past for parades and public events in Japan. I bought it years ago from the Washington DC office of the Japanese RICE University, it was the one that stood in the entrance area. Comes with the original storage box. - According to the dedication inside the box, it was given to a professor in 1987. I do not know the age of the armor (evidently much older than 1987). Note that it is quite heavy.
As for the age, there are similar Samurai armors for sale. Note this Japanese Samurai Yoroi Armor from 1920-1940 (which has an identical transport box): https://kurayaantiques.com/product/27286/