I have a Hook section on my web-site
http://donaldnicolson.webplus.net/page204.html

This is a precis of some of the info:-
Drennan Super Specialist Hooks - This is the heavier hook.
Drennan Carbon Specimen Hooks - My preferred hook for Spiders.

These two hooks are marketed in the UK by Drennan under their name,
but are made for them by Daiichi.

Many US anglers use
Daiichi 1640 Multi-Use Dry Fly -
Which is the same as the Carbon Specimen.

Daiichi 1110 Wide-Gape Dry Fly Hook.
Model perfect bend, oversized straight-eye, 1X-fine wire, "mini-barb", bronze.

This hook is marketed by Orvis under their own name.

I have no direct evidence, but it seems quite likely that the
Kamasan hooks are actually made for the European market
by Daiichi. Some of the patterns are the same, but there are hooks
in the Kamasan catalogue that are obviously quite specific for the
UK market.