however the late verktyg (AKA Chas) corrected juvela (and me, too cause I repeated the "SR" ID) that these cranks with the "crest or shield" and double line fluting on the arms was made by Tagaki and not Sakae Ringyo. And this shield has "BS" emblazoned on the eagle, which is because all or most were used on Bridgestone bikes, originally, but as with many parts, they can get around...
But if it's any consolation Tagaki and Sakae Ringyo were both members of the "JDM" manufacturer's group (which also consisted of Shimano, Tange, Araya and KKT/Kyokuto)
and AFAIK it's only some of the SR cranks that used this 3-degree taper, not any the Tagaki cranks