A very large, and important section of Tezuka's manga catelogue are his short stories. With an imagination as active as his, the need for creative output would often outpace his ability to incorporate his ideas into his longer story-form manga serials.
The Crater (1969-70) has the distinction of being one of the inaugural features in Weekly Shonen Champion - back when it was still just known as Shonen Champion! Regardless, the magazine would later go on to become the home to some of Osamu Tezuka's most important manga series, notably Black Jack (1973-83), Alabaster (1970-71) and Rainbow Parakeet (1981-83).
Ongoing Serial: a series of episodes, published over a span of weeks/months/years where the story plot is connected from chapter to chapter and must be read in chronological order for it to be understood properly.
Chapter Serial: a series of episodes, published over a span of weeks/months/years where the story plot is self-contained to a single chapter. There may be an overarching plot, but the stories can generally be read in any order and be understood
Book: an all-in-one self contained story published as a one-off.
Supplement: an an all-in-one self contained story published as a stand-alone supplement to a regular weekly/monthly periodical.
Short Story: an all-in-one, self contained story that was published in a regular weekly/monthly periodical
Anthology: a collection of all-in-one, self contained stories that were published in a regular weekly/monthly periodical but are generally grouped together.