What kind of glass is the 'HS full-surface ion-toughened glass' stated in the drinking glass description?

HS refers to the Hand Strong line presented by Toyo Sasaki with enhanced durability for everyday use^[1]. The 'full-surface ion toughening' added to the name is a chemical method where glass is immersed in a special solution to exchange small sodium ions on the surface with larger potassium ions, densely tightening the surface. Unlike physical air-blast quenching, which heats the glass to high temperatures and cools it, it does not make the glass thick, creating uniform compressive stress across the entire surface even with a thin profile.

The base material is transparent and familiar soda-lime glass^[2]. Through the ion-toughening process, the glass retains its light, thin shape while withstanding everyday impacts more firmly^[3]. In particular, by reinforcing the durability of the lip line—the rim that makes contact first when clinking against other tableware or when drinking—it provides both the delicate feel characteristic of thin glasses and practical sturdiness^[4].