70s vintage Japan stoneware stackable mugs, retro speckled glaze blue & yellow

Cute 1970s vintage mugs made in Japan, a brown spatter pattern white with blue and yellow interiors as shown.

These are nice and heavy, 10 ounce size, about 3 3/4" tall. All four mugs are in very good clean condition - a few makers flaws but no damage or noticeable wear.