20th Century Japanese glass

Prior to the 20th Century, glass making in Japan was not an important industry. They just had little use for it. Even the now ubiquitous Japanese fishing floats are a 20th Century development. "Art glass" was generally of the cut crystal (Edo kiriko) type made for export and for the very wealthy. World War I changed everything. Japan's light industry was geared up and eager to fill the void created by European shortages. This sort of glass ware was not really a product meant for domestic consumption in Japan. It was generally made for foreign markets. America and the United Kingdom got the bulk of it. As the European goods returned to American markets after the war, Japanese goods began getting the reputation of "cheap imitations".

This initial surge of Western imports soon dried up as political issues interfered. World War II found Japan and most of the rest of the world on opposing sides. When the war ended, Japan's industry and economy needed major rebuilding. Leading the way in this recovery were the surviving ceramic and glass manufacturers. Another surge of exports began in the early 1950s.

As I understand it, much of the 1950's glass exports were the same as, or very similar to, the 1930s glass, so, at least for now, it is difficult to accurately date. By the 1960s, importer's stickers and changing styles begin to clarify (at least) the dating. Tracking down the actual makers of these pieces is in its infancy. These pieces most likely date from one of those early surges.

1 - Vase, multicolor spatter, 15 cm (just under 6"), acid stamp mark. (1930s?)
2 - Pair, multicolor spatter, taller vase is 15 cm (6"), clear added base impressed JAPAN; shorter vase is 12 cm (4 3/4"), black added base, unmarked. (1950s?)
3 - Small vase with light spatter, added black base, 9 cm (3 1/2"), unmarked. (1930s?)
4 - Bud vase, striated blue with added black base, 17.5 cm (7"), impressed circular mark. (1930s?)