Unico is a fairy-tales-like shōjo manga from Osamu Tezuka. It was started in 1974 in the short-lived magazine called Ririka.


Tezuka is known for crafting some of the first notable shōjo manga, with for examples Ribbon no Kishi in 1953 or the shōjo version of Hi no Tori in 1956. Those stories were for their time quite interesting ; definitely cute, stereotyped but with some little twists here and there, with cartoonish humor and compelling stories.


But then, 20 years after, in 1974 Tezuka did a new shōjo again, Unico.
Basically Unico is the same than those two manga, but without any humor, the little twists aren't there either, and there no real story anymore : you just repeat again and again the same motif because Unico forget everything between each chapter.
That's the main issue of that manga : no story, and thus no real character. It was really a boring read.

The other issue is simply that between Ribbon no Kishi and Unico, the content didn't really evolved, yet there is 20 years of difference between the two works. During those 20 years, there was some authors like Hideko Mizuno, Moto Hagio, Yumiko Ooshima and others who really changed the face of the shōjo manga, with more deep and complex stories and characters.
Tezuka said it himself in the postface of Unico : Unico is anachronistic, by being too smooth, too cute for being cute and with too flat, one-dimensional characters. You can't compare Unico to, for example, Wata no Kuni Hoshi from Ooshima, another manga for young girls from the same period than Unico.
Tezuka is known for being a precursor, but with Unico, he was really has-been.


Is Unico a bad read? No.
But if you are planing to read some old shōjo from Tezuka, you might as well read Ribbon no Kishi or even Hi no Tori that are more interesting in my eyes, more compelling.
And anyway, Unico was published 10-15 years too late.