The two types of shakuhachi are jinashi and jiari (地無し and 地在り) with variations of each. Historically, the first types of shakuhachi were jinashi while jiari came about much later. Jinashi are all or mostly natural bamboo on the inside of the bore while the bore of jiari are completely shaped with layers of plaster. The first jiari were made by applying many layers of a paste called ji, however, today jiari are mostly made by using various casting methods.
The first individual to be credited with augmenting the inner bore of a shakuhachi with ji-paste was a “Grandmaster” of the shakuhachi named Araki Chikuo (1823-1908). Lastly, there are shakuhachi called Hocchiku (法竹) which are modern, large bass jinashi. Hocchiku were created and popularized by the master Watazumi (1910-1992). They’re much larger than the jinashi that were used by the Komuso monks of the Edo period.