It isn't known exactly how tobacco first came to Japan. In the mid-to-late 16th century, tobacco was spreading in East Asia and South-East Asia, probably through multiple routes: Portuguese sailors/traders from Europe or Brazil, Dutch sailors/traders, Spanish sailors/traders from Mexico and the Philippines, and Arab and Indian sailors/traders. By one or more (and most likely it was through multiple routes), tobacco was known around the East and SE Asian maritime world in the 16th century. But the early 16th century it was being grown in China and Japan.

The 16th century also saw the rise of the tea ceremony in Japan. Tea already had a long history in Japan, having been introduced from China and grown in Japan in the early 9th century. The classic tea of the tea ceremony, made with matcha powder, arrived in China in the 12th century, and was drunk by Buddhist priests. It spread to the samurai class in the 13th century, and was popular in the 14th century. The tea ceremony, as opposed to merely drinking tea, was assuming a recognisably modern form in the 16th century, brought into this shape by the first recognised tea masters. Perhaps the most famous and influential of these tea masters was Rikyū, who smoked, and might have introduced smoking tobacco to the tea ceremony. Smoking as part of the tea ceremony did help spread smoking in cultured elite circles in Japan. If Rikyū was responsible, the inclusion of smoking in the tea ceremony took place before his death in 1591.

Japan was already exporting tobacco to SE Asia by 1634, so production was well-established by then.

For a brief summary of the introduction of tobacco to Japan, see

• Barnabas Tatsuya Suzuki, "Tobacco culture in Japan", pp 76-83 in Sander L. Gilman and Zhou Xun, Smoke: A Global History of Smoking, Reaktion, 2004. Further chapters discuss Edo Period smoking in Japan, and also modern Japan.

There is also discussion of the early history of tobacco in East Asia in

• Benedict, Carol, Golden-Silk Smoke: A History of Tobacco in China, 1550-2010, University of California Press, 2011.

In both of these books, one thing that stands out is that we don't know much about the details of the introduction of tobacco in either Japan or China. By the time we have good evidence, it's already there, and being smoked.