decade, to the illustration of those small works of popular fiction which, from their yellow covers, are called Kibiyoshi (yellow books). From as early as 1785 on, two pupils collaborated with him, Mitimaro and Yukimaro. All these illustrations were printed in black and white. In the year 1786 his first book of erotic contents was produced in collaboration with Rantokusai, in which he still signs with his own name. From 1787 onward he published, still always in black and white, a series of books of larger size, and at the same time, in 1788, the splendid book of insects, printed in colours, for which his teacher Sekiyen wrote an epilogue attesting his touching love for his pupil and taking, remarkably enough, the form of a eulogy upon the naturalism reintroduced into art by Utamaro. Here, he says, are the first pictures painted with the heart. About this time, which marks his nearest approximation to Kiyonaga, he probably produced the book of shells, finely drawn and coloured with all the subtlety of the later surimono, in which the figures at beginning and end remind us strongly of that master. Kurth (Utamaro, p. 41) assigns it to the period around 1780 (see also his pl. vi.). The third of his books of natural history, the Hundred Screamers (birds), the finest of all his work, probably did not appear until the nineties. Kurth (ibid., p. 76) assigns it to so early a period as about 1789. Utamaro had also announced the publication of a book of mammals and a book of fishes, but these were never executed. In the year 1788 further appeared The Poem to the Pillow, with colour illustrations, the finest of his erotic works; lastly, in 1789, Verses to the Moon, and an erotic volume.
His illustrated books continued in the nineties, but dates more rarely appear. Of those printed in polychrome, except the Testing of the Pines, of 1795; the Flowers of the Four Seasons, of 1801; the Fallen Blossoms, of 1802; and the Green Houses, of 1804, only the Promenade at the Time of the Cherry
