The humble 4-koma: a style of manga featuring four panels aligned vertically; otherwise known as yonkoma or four panel manga. Most examples are found acting as a complement to series, an extra bonus awaiting those who acquire the bound volumes. Look no further than Hayate the Combat Butler, Genshiken, or The World God Only Knows for plentiful examples. They are also found in Japanese newspapers and magazines, akin to our own political cartoons. They are short, sweet, and relatively ubiquitous.
Yet, some manga use the format for the series itself. Again copious examples may be found, some of which have anime adaptations. Hidamari Sketch, K-On, Lucky Star, and the recently adapted Kill Me Baby, are just a few examples. All are generally light series, never straying too far from a slice of life and mostly including comedic elements. Indeed, the style itself is effectively defined by light, airy comedies.
Yet, there are always exceptions to a rule, and it is these exceptions that I find affecting.