“One of the great defects of English books printed in the last century is the want of an index”.
Hearn’s point is that Japanese poetry is regularly ‘double-indexed or even quadruple-indexed’ so that key themes ‒ pine trees, the beauties of the autumn season, for example ‒ are quickly found by a student who wishes to discover all that has been written on a particular subject. By contrast, English poetry is usually only indexed by the first line.
One of the essays is about Ko-kwai, a curious incense-burning guessing game played by Japanese families and their guests. It involves burning packets of different kinds of incense (cherry blossom in mist, young bamboo) in a closed room and then afterwards trying to guess which fume is which. Hearn goes into the mechanics and the scoring of the game at great length, but my eye was caught by this passage:
“It is the custom in some families to enter all such records[of a Ko-kwai game] in a book especially made for the purpose, and furnished with an index which enables the Ko-kwai player to refer immediately to any interesting fact belonging to the history of any past game.”