The Ōbaku-shū (黄檗宗) is one of several schools of Zen in Japanese Buddhism, in addition to Sōtō and Rinzai.
Often termed the third sect of Zen Buddhism in Japan, it was established in 1661 by a small faction of masters from China and their Japanese students at Manpuku-ji in Uji, Japan.
Today Manpuku-ji serves as the Ōbaku's head temple, with 420 subtemples spread throughout Japan as of 2006. In addition to their contribution to the culture of Zen in Japan, the Ōbaku also "disseminated many aspects of Ming-period culture" in the country. Many of the monks who came from China were accomplished calligraphers, and Obaku's founder Yinyuan Longqi and two other Ōbaku masters, Mokuan Shōtō and Sokuhi Nyoitsu, became known as the Ōbaku no Sanpitsu (or, the "Three Brushes of Ōbaku"). Author Steven Heine writes, "Areas where the influence of — or the reaction to — Ōbaku left an imprint on Japanese Buddhism is manifold, and its impact even reached the fields of Japanese cultural techniques, such as printing and painting. Chinese medicine and architecture were also introduced, as was the practice of "spirit writing", the latter practiced by Ōbaku monks who were said to communicate with Chen Tuan.
Rooted in the lineage (school) of Linji, and therefore sharing a familial relationship with the Rinzai-shū of Japan, the Ōbaku's approach to practice is today tinged with a hint of Chinese influence. More narrowly, Ōbaku abbots are now all from the Ōtōkan lineage, the same as Rinzai, and thus practices are largely similar, though this was not the case originally. Historically, the Ōbaku-shū has sometimes been referred to as "Nembutsu Zen"—a derogatory characterization intended to describe their use of "Zen and Pure Land practices." Helen J. Baroni writes that today, "With a few notable exceptions, such as the style of sutra chanting (which continues to be done in an approximation of Fujian dialect), Ōbaku temples and monasteries appear very like their Rinzai neighbors." Statistically the smallest school/sect of Zen in modern-day Japan, the Ōbaku is also like the Rinzai-shū in that it is known to be more conservative and intellectually inclined than the Sōtō-shū.