Ninna-ji has two tea houses, Hito-tei, which sits on manmade hill beyond the pond in the North Garden, and Ryokaku-tei which is surrounded by trees behind Remeiden. In winter when the trees have lost their leaves it will be much easier to see Ryokaku-tei than is it now, but if you peer between the tree branches from Remeiden, you should be able to catch a glimpse of it.
Ryokaku-tei was originally the residence of the painter Ogata Korin (1658-1716) and was moved to Ninna-ji during the Tempo Era (1830-1844). When Ryokaku-tei was built, it was designed to resemble a famous tea house called Joan (joe-ahn). Joan was built in Kyoto in 1618 by Oda Uraku, tea master and the younger brother of the infamous Oda Nobunaga. The tea house was moved from Kyoto in the late Meiji period and came to its present location in Inuyama City, Aichi Prefecture in the 1970s. You can see a couple of pictures of Joan here. The buildings are really quite similar, but you know what they say — imitation is the sincerest form of flattery.