333 is the old brand symbol for Shimano and appeared on all their products. It goes back to the establishment of the company in 1921 and reportedly first appeared on the 1922 frreewheels. It was designed to be similar to the British Small Arms trademark symbol, a rifle manufacturer who had gone into bicycle production in the 1880s and was held in high esteem in Japan. I suspect the numeral 3 was chosen for its status as a lucky number in Japan.

BSA was so highly regrded that several other Japenese companies designed similar trademarks, including SunTour (8.8.8) and Takagi (3 Arrrows).

Shimano introduced their current elliptical symbol around the time that Dura-Ace was introduced. Still, the old 333 symbol remained on some of the older products, through the boom, until they were re-tooled or discontinued.



I have an Arai motrocycle helmet too, though I only used it for about a handful of years, before I stopped riding motorcycles circa 1986. When I bought it , around 1980, Arai wasn't very well known in North America. They had only been importing for maybe a year or two. If I recall correctly, it's the original version of their Astro, full face helmet.