The Ships list. com has this to say about the Tenyo Maru:
13,454 gross tons, length 558ft x beam 61.9ft, two funnels, two masts, triple screw, speed 20 knots, accommodation for 275-1st, 54-2nd and 800-3rd class passengers. Built 1908 by Mitsubishi Dockyard & Eng. Works, Nagasaki for Toyo Kisen K.K., Tokyo and used on Hong Kong - Yokohama - San Francisco passenger services. In 1926 the company became Nippon Yusen K.K., Tokyo. 1930 laid up, 1933 scrapped in Japan.
This postcard shows the reading room with its amazing furnishings. The ship is initially reported to have had a room where Chinese passengers could go to smoke opium. There must have been a limit to the amount though. Other reports I have seen (including one in the Overland Monthly, Volume 58, 1911) refer to opium being seized in searches of ocean liners coming from the Orient. In one seizure in 1911, eighty tins of opium were taken from the Tenyo Maru.
My favorite story is from Time Magazine, 1929, which details the plight of Mrs. Sui'e Ying Kao, wife of the Chinese Vice Consul at San Francisco, who imported a large quantity of opium on the Tenyo Maru, thinking that she had diplomatic immunity. Alas, the customs agents disagreed. They confiscated $600,000 worth of opium (1929 prices!) from Mrs. Kao. In any case, the reading room shown above seems like the perfect place for smoking opium.
Here's the back of the card.