shuboku 主木

Lit. "master tree." The tree planted on the top, front of a garden hill *tsukiyama 築山 to serve as the central focus of the garden. This design had its genesis in 16th-century pond gardens, and then evolved into the use of two trees, one leading left and the other right, in 17th-century gardens. In 18th-century hill gardens, a single tree (sometimes called *shōshinboku 正真木) became the standard type of shuboku. The second volume of *Tsukiyama teizōden 築山庭造伝 states that in formal style tsukiyama, a pine matsu 松 and oak kashi 樫 may be used, but in semi-formal style gardens a willow yanagi 柳 and cherry sakura 桜 are used. In flat gardens, the master tree is called *shugoboku 守護木 (guardian tree).