It would be interesting to have further links/resources/research.

Apparently, Japan reigns supreme in the manufacture of mechanical pencil components w/ brands such as Rotring and Skilcraft importing, or contracting to Japanese companies either for manufacture (my Rotring Quattro is labeled as Made in Japan), or parts sourcing (my Skilcraft B3 Aviator multi-pen was noted as including mechanical pencil components imported from Japan).

One of my favourite mechanical pencils is a "357" imported from Japan which uses a Rotring-like gravity mechanism to select a 0.3mm, 0.5mm, or 0.7mm lead.

Wasn't always so --- I can still remember playing w/ a Norma 4-colour mechanical pencil my father had (which sadly wasn't among his effects when he passed --- just ordered a replacement off eBay...) Unfortunately, the page on this at: http://www.roger-russell.com/ is off-line.