To start part two, here's a useful list of sources on the history of women's literacy in Japan:
Link to Women and Books in Japan (Cambridge)
Okay, back to Onna daigaku. We've now reached the Kyoho period. Ishikawa tells us that in 1716, there was the simultaneous Osaka-Edo publication of Onna daigaku takarabako, the first of a flock of similarly-named texts. It followed the example of Onna Imagawa and Onna jitsugokyô in organization and content, arranged in the form of admonitions. Similarly, aside from being a reader, it was also a calligraphy copybook. Furthermore, it was profusely illustrated.
According to Ishikawa, it's not clear why this (these) texts were called Onna daigaku. The editor is not named, there is no preface, and there's no indication in the main text either. It's entirely speculative to say so, but during the early modern period education for boys was drawn from Confucian curriculum, Song studies (= neo-Confucianism) was very influential, so the Four Books was the basis of education. The Four Books were Daxue, Zhongyong, Lunyu, and Mengzi, and of these, Daxue was the most important. So, perhaps Onna daigaku was thus named in order to function in girls' education the same way that Daxue did for that of boys? In other words, girls should have it to hand, internalize its principles -- the first, most important moral textbook.
Click "read more" for the rest.