Translator’s note: Katsu means “arrowroot” and to means “wisteria.” Arrowroot and wisteria, being vines, are unable to stand by themselves but grow by entwining with other plants. Because of this, in China and Japan, arrowroot and wisteria are used as a symbol of something that is very complicated. Buddhist philosophy strives to describe what reality is. Because reality cannot be adequately expressed with words, it is sometimes described as “the ineffable.”

--Dōgen, chapter on Kattō