Ishii Seijun 石井清純, Zen mondō nyūmon 禅問答入門 [Introduction to Zen dialogues], Kadokawa Sensho 463. Tokyo: Kadokawa Gakugei Shuppan, 2010, 254 pp. ¥1,575, paper. isbn 978-4-04-703463-1. Okimoto Katsumi 沖本克己, Jōshū: Hyōhyō to Zen o ikita tatsujin no azayakana fūkō 趙州-瓢瓢と禅を生きた達人の鮮やかな風光 [Zhaozhou: Vivid portraits of a master who lived Zen as a free spirit]. Tokyo: Kadokawa Shoten, 2008, 214 pp. ¥2,730, cloth. isbn 978-4-653-03996-9. Yanagida Seizan 柳田聖山 and Umehara Takeshi 梅原猛, Mu no tankyū (Chūgoku Zen) 無の探求 (中国禅) [Investigations of nothingness (Chinese Chan)], Kadokawa Sofia Bunko. Tokyo: Kadokawa Shoten, 2009 rpt., 385 pp. ¥800, paper. isbn 978-4-04-198507-6.