Iwatsu Glass (Japan)

Based in Osaka, Iwatsu Glass stands as one of Japan's most recognised and prolific manufacturers of mid-century art glass. Operating at the height of the country's post-war manufacturing boom, the furnaces produced an outstanding volume of high-quality decorative wares that rivalled the output of traditional European glasshouses on the global market.

The company reached a creative and production peak during the 1960s and 1970s, releasing a diverse range of vases, centrepieces, and art glass pieces. They captured the aesthetic of mid-century modern design, frequently featuring vibrant swirls of colour cased in thick, clear glass.

What truly sets Iwatsu apart for collectors is their approach to colour and form. Their most famous export line, the Hineri range, is known for its ribbed, highly tactile bodies that capture and refract natural light. From multi-coloured 'Rainbow' designs to their pulled 'handkerchief' vases, Iwatsu's makers blended the bold vibrancy of the 1970s pop-art movement with a Japanese reverence for organic, fluid shapes.

Because Japanese art glass from this era was so heavily exported, authentication often relies on surviving paper or foil stickers. Pieces destined specifically for the international export market were predominantly branded as Hineri Glass, while those sold domestically within Japan usually carried an Art Glass label. Both variations frequently feature the Iwatsu logo and occasionally the characters '手作り' (translating to 'handmade'). Additionally, it isn't uncommon to find Iwatsu's glassware distributed under the branding of other Japanese export companies, showcasing labels from Kamei Glass or Nanbu Glass rather than the factory's own mark.

Read more about Japanese glass production here.