Check out some of the 0.25mm and 0.18mm (!) pens available from Japan. Really, really fine-lined pens are something of a fetish there. jetpens.com sells a bun

Check out some of the 0.25mm and 0.18mm (!) pens available from Japan. Really, really fine-lined pens are something of a fetish there. jetpens.com sells a bunch of Japan-only imported pens and other writing tools.