I remember seeing the Mitsubishi DEMI-.5 posted here a couple months ago and decided to dig deeper. Part of the fascination is trying to find out if this was the earliest 0.5mm MP that they made, or at least, the earliest that was deemed worthy of export to the USA.
I soon obtained two DEMI-.5 in green and Mitsubishi’s signature reddish brown. And several months later, secured what I believe is the domestic equivalent: Holder 305 or M305 as the listing claimed.
Comparing the brown DEMI and 305, there are obvious similarities, although the styrofoam packaging is slightly different.
For example, the arrangement of the mold, the stickers for the leads, and how the lead hardness for the 305 was left to the owner to decide what to stick onto the pencil body.
Both versions came with a separate cleaning pin as well. Not pictured, but the clear case cover will fit either foam case.
One of the curious differences is the length of the guide pipe. On the domestic 305, the tip is roughly 2.5mm. The imported DEMI-.5 came with 2 versions: the same 2.5mm tip OR a super long 5mm pipe. This gives the pencil a lethal appearance!
A closer look at the brass clutch. There are identical to my eyes. The cones will fit either version with no problems.
And of course, these primordial 0.5mm designs carry over the ‘one stick of lead in one tube’ philosophy of the preceding 2mm lead holders.
Here, the 305’s clip sports the distinctive Mitsubishi logo. I think the importer Yasutomo may have been deliberate in creating the ‘DEMI-.5’ branding to avoid any anti-Japanese bias in the US market back in those days.
From my own research, the DEMI-.5 was advertised as early as 1966 in the October issue of Progressive Architecture:
This is interesting as the generally accepted dates for introduction of 0.5mm polymer leads was 1962 for Pentel, Faber-Castell in 1967 and Mitsubishi in 1968. Given the known cooperation between FC and Mitsubishi for various fine lead MPs, it is possible that the leads supplied with the DEMI-.5 were by FC. Here is a reddit post by First Sail of the DEMI branded version of the M5-50 Hi-Pitch Holder that was also sold by FC.
One last shot of the DEMI-.5 and Holder 305 series. Seen here is a black version of the DEMI-.5 that I picked up without a box.
From eBay listings, it seems Yasutomo would continue to market the DEMI branding with updates to the pencil design and mechanics. But for me, this is probably the closest to an equivalent to the PENTEL 100/101 or 350D.