A number of essays, theses, and monographs on Hakuin have been published, but they are relatively few in number compared to the amount of material on other popular Zen figures like Ryōkan 良寛 (1758-1831) and Ikkyū 一休 (1394-1481). The published material is, moreover, of questionable quality.

In 1997 an Italian doctoral candidate I know researching Hakuin for her dissertation found 120 Hakuin studies listed on the Internet, but read no more than three or four before concluding that all were simply rehashings of the same material. Her impression was correct. The existing literature on Hakuin contains little solid academic research; most is expository material falling into one of three categories:

1. Hagiographies, centering on Hakuin’s childhood terror of hell and his trancendence of this fear through Zen training.
2. Health manuals, explaining Hakuin’s method of “introspection” (naikan 内観) as presented in works like Yasen kanna and Orategama.
3. Essays on the Zen paintings of Hakuin.

In 1996 the Zen Bunka Kenkyūsho (Institute for Zen Studies) initiated a project to issue annotated editions of all of Hakuin’s writings. As chief editor, I embarked on the project feeling that I basically understood Hakuin, but that he was far from my favorite Zen master. My impressions had been largely formed by the sort of stereotypical accounts mentioned above, which focused on the childhood stories of Hakuin and on the sometimes heavy-handed cause-and-effect tales (inga banashi 因果話) in his Japanese writings (kana hōgo 仮名法語).

I was hardly alone in this aversion — the late Buddhist scholar Kamata Shigeo, for example, wrote, “Many people do not like Hakuin, for various reasons. Some, for example, cannot agree with the severe, almost harsh, methods of training he advocated; others find his Japanese kana writings to be lacking in refinement” (Hakuin, Nihon no Zen goroku 19, Kōdansha).

As work on the project progressed, however, my views of Hakuin gradually changed. I realized not only how narrow my understanding had been, but that my “understanding” was nothing more than an uncritical acceptance of the cliches presented in the standard literature on this master. Greater familiarity with Hakuin’s writings showed that the existing scholarship, though accurate enough in certain respects, has failed to provide a complete picture of the master’s life and thought.