To meet the Japanese American artist behind Seattle’s “From Hiroshima to Hope” posters, you need to travel to a castle in Tacoma: the Tillicum Building, designed in 1929, shaped like a castle from the outside. Once you arrive, expect a cheerful studio and shop full of natural light, boxes and boxes of brightly colored letterpress cards and envelopes, intricately carved woodblocks leaning against the windows, and even several small birds who twitter happily in their cages.