The old Mitsui Club, built in 1921 as the Moji branch of the powerful Mitsui trading conglomerate, is a half-timbered Tudor-style building down on the harbour at Mojiko. It once hosted business meetings, dinners, and visiting foreign dignitaries — most famously Albert Einstein, whose visit is commemorated by a small exhibit on the upper floor.
Today it functions partly as a free museum and partly as a working restaurant; the wood-panelled rooms and original furniture are largely intact. Worth half an hour. Combine with the nearby Old Mitsui Bussan Building, the Old Customs House, and a slow walk along the quayside.