Perhaps for the reason that Ukiyoé themes were not considered quite dignified, and because they did not express poetic ideas, the Ukiyo paintings of Matahei and his contemporaries and successors, though prized and much sought after, were seldom signed, and the identification of their authorship is a matter of extreme difficulty. For more than half a century works in this manner continued to be produced in considerable numbers, but the movement did not crystallize into a school until, in the person of Hishikawa Moronobu, a leader appeared to give it form and direction. Moronobu was an artist of rare distinction. His paintings were eagerly sought by the daimyos and the wealthier samurai. But Moronobu was a man of the people, and it was as a designer of book illustrations and later of ichimai-yé, or single-sheet prints, that he gave the impetus to Ukiyoé. For fifty years or more prior to his time books with engraved illustrations had been published in Japan, but they were comparatively few and the illustrations were poor and crudely executed. The twelve drawings Moronobu made for a book of instruction for women in etiquette and hygiene, published in 1659, marked a decided advance. This, so far as we know, was the first of a long series of books illustrated by him. Their popularity was deservedly great, and by them his fame became wide-spread. The illustrations were printed in black from blocks similar to those from which the text was printed, and were characterized by fine broad treatment and a rather wiry but strong and expressive outline. About 1670 Moronobu began to issue large single-sheet prints which could be affixed to screens or mounted as kakemono. These prints, which were impressions in black from one block only, are known as sumi-yé—_sumi_ being the Japanese name for Chinese—or, as we incorrectly call it, India—ink. They were designed to be coloured by hand, and apparently a part of the edition was so coloured before being placed on sale by the publishers. At first this colouring consisted of a few touches of yellow-green crudely laid on; later it became more elaborate, and occasionally we meet with prints that are very beautifully coloured, but in such cases it is impossible to tell when or by whom the colouring was done. The probability is that in some instances it was the work of purchasers of the prints.