A-rin has been registered as a trademark.

According to information on the Patent Information Platform (J-PlatPat), the name 'A-rin' has been registered as a trademark.

https://www.j-platpat.inpit.go.jp/t0201

The applicant is Stardust HD Corporation, and the scope of the application covers "personal effects made of cloth (towels, handkerchiefs, bedding, blankets, etc.)" and "clothing, bands, belts, footwear, fancy dress clothing, etc.".

The name applied for is written in hiragana as 'あーりん'.

It is a mystery why only 'A-rin' was registered, and not 'Shiorin' or some other name.