To boil water, one needs a heat source, water and a container. Simple enough. Nevertheless, even if limited to just containers, countless commodities surround us. A two-liter, aluminum kettle is probably sufficient for the majority of one's needs, but there are also big kettles to make large quantities of barley tea and Nambu ironware that might be used over an open hearth. There are kettles with copper coils wrapped around their base to improve thermal efficiency, and kettles with bird miniatures attached to their spouts that chirp when the water is boiling. Such is the diversity that material quality, capacity and design all differ in any type of kettle.

One could probably say this about almost all commodities, too. They branch out from an original form, become segmented, deviate, revert, try various permeations and combinations, become multi-functional or, the other way around, narrow and focus their functions. Before you know it, we are surrounded by endless variation. Desire generates commodities and commodities generate desire, and the circular dance goes on and on indefinitely.

Eromanga has also given birth to commodities or works corresponding to just about every conceivable desire. This begins with third-rate gekiga and expands explosively in bishōjo-style eromanga, or what was in the early days called lolicon manga. Such is the range and diversity of eromanga that it appears almost a mirror reflecting our polymorphous desires. Here I divide the various forms of desire seen in eromanga into a total of seven chapters, which cover lolicon, big breasts, little sisters and incest, disgrace and training, love stories, sadomasochism and sexual minorities and gender mayhem.