Ashita No Joe c. 1971 : Creation of the postcard memories technique

Osamu Dezaki was a lion among animators, renowned for his work on such anime as Astro Boy, Dororo, Lupin the Third, and Space Adventure Cobra and whose signature techniques have since become inseparable from the visual language of Japanese animation. His most enduring contribution to the medium of animation comes in the form of his “postcard memories” technique, a stylized form of denouement shots that has been all but unanimously adopted by countless anime directors since the 1970s.

Characterized by a freeze frame resembling a faded pastel-chalk portrait painted on a postcard, hence the name, the “postcard memories” technique is a form of limited animation that’s been used to emphasize humor, drama, romance, action, or melancholy. This last quality is on full display in the closing shot of the 1970 boxing sports anime Ashita No Joe, Dezaki’s directorial debut, where the protagonist Joe Yabuki, following his defeat at the hands of his rival José Mendoza, slumps over in his corner of the boxing ring deathly still, a faint smile eerily painted across his face. The “postcard memories” technique has since transcended its creator to become one of the most ubiquitous visual tropes of Japanese animation, seen everywhere from Dragon Ball Z to Cowboy Bebop to Kill la Kill and beyond.

https://www.vulture.com/article/most-influential-best-scenes-animation-history.html