Iida's scholarship is particularly noted for his pioneering research on the Madhyamaka philosopher Bhāviveka (Bhavya), then a little-studied figure, conducted in part among Tibetan refugee communities in India; this work culminated in his study Reason and Emptiness: A Study in Logic and Mysticism. His other major publications include Ocean of Eloquence (1993) and the essay collection Facets of Buddhism (1993), which gathers roughly twenty years of his scholarship and reflects his trajectory from a specialist in classical Indian and Tibetan Buddhist philosophy toward broader comparative religious studies—encompassing subjects such as the "sudden versus gradual" enlightenment debate (including work on the thirteenth-century Sakya master 'Phags pa), Buddhist themes in Japanese Noh theater and in Yukio Mishima's fiction, the modern Soka Gakkai movement, and points of convergence between Buddhist and Sufi thought. Through both his translations and essays, Iida played a role in bringing Japanese-language Buddhological scholarship to English-speaking audiences.
