Shakyo, hand copying Buddhist sutras, descends from a devotional practice attested across the wider Mahayana Buddhist world, in which the physical act of transcribing scripture is itself understood to generate merit for the copyist, comparable in the tradition's own logic to reciting or venerating the text, since the sutra's teaching is treated as worthy of the sustained, attentive labour copying demands regardless of whether the resulting copy is ever read by anyone else.
In Japan the practice is most commonly associated with the Heart Sutra, the short and famously dense Prajnaparamita text whose brevity, some two hundred sixty Chinese characters in its standard Japanese liturgical form, makes it practical for a single sustained sitting in a way longer sutras are not, though other short devotional texts are also copied depending on temple and school. Many Japanese Buddhist temples, particularly though not exclusively within Zen and Shingon traditions, provide shakyo sessions for visitors, supplying brush, ink and guide sheets on which the sutra's characters are printed lightly for the copyist to trace over, a practical accommodation that has made the practice widely accessible to lay visitors and tourists with no calligraphic training rather than confining it to trained monastics and dedicated practitioners alone.