Osaka has an infrastructure to help the blind find their way. The city's yellow bumpy paths make following with a cane easier; finding intersections through variation in the shape of the bumps is also easier. Well placed Braille signs appear in all the subway stairwells, explaining where passages lead. Handrails supply information in braille! This pin is one such handrail.
I see a "B" and a "Number Sign". A great way to find hidden Braille letters after a game of Tic-Tac-Toe. Just turn the board around to find new letters/contractions. An idea from Merry-Noel Chamberlain, TVI.