The legendary Han-dynasty explorer Zhang Qian is engaged in an unlikely endeavor—white-water rafting. As immortalized in a Yuan-dynasty poem, he rode a log raft in his attempt to discover the source of the Yellow River; instead, he found himself afloat in the Milky Way. The dark strokes that delineate the bamboo disturbed by the water heighten the sense of turbulence, and the pale ink wash on the raft evokes the plasticity and buoyancy that kept the hero afloat. The subject, seldom represented in Japanese painting, was most likely inspired by a Chinese model.

The scroll bears two seals reading "Maejima" and "Soyu." Details of this painter's life are not known, but works bearing the same seals have been discovered that help to identify Soyu as one of the few artists from eastern Japan (Kanto), then considered culturally backward. Some of his paintings have been erroneously attributed to leading Kano School members, suggesting that Soyu studied with a Kano master in Kyoto.

This work is Soyu's only known figure painting. The dramatic wave treatment and jagged, nervous drapery folds indicate that it may belong to Soyu's early period, before he became acquainted with the more sophisticated Kano painting that influenced his landscapes.