Graphic art style mid-century mod vintage china plates, made in Japan. This pattern is called Carnival, so I'd guess these are beads, but they look like marbles or gumballs to me! I love the primary red, blue and yellow with the black against the white plates.
It's a set of four plates 7 1/2" square. All four are in very good condition - no chips, very little scratching or wear from use.