Vintage Japanese “Sunlight” pen with built-in battery powered light

An unusual and well-made pen with a twist, literally – turn the nurled end of the Sunlight pen’s barrel and the clear section of the pen lights up. The light is battery-powered (the battery is in the main part of the barrel) and the bulb still works. A small hole in the barrel indicates whether the light is on whilst the cap is in place over it. The pen refill doesn’t seem to offer any ink so this is probably more of a curio than a functioning writing implement. It may be remediable. The pen is approximately 14cm in length (5½ in.) and takes a “AAA” size battery.