One of the more unknown and interesting areas to collect is the Koban issues of Japan. Unlike the first two Japanese issues which have been extensively forged (actually faked #1-8 of Japan are about ten times more common than the genuine, and forgeries of the second Japanese issue, called the Cherry Blossoms, are ubiquitous too), the Kobans are nearly always genuine and very plentiful. They were the main stamp issue of Japan for the 1875-1910 period, which coincided with one of the most significant and rapid industrializations that any nation has undergone. In 1868, Japan had been a feudal state nearly cut off form the world. The Meiji Restoration changed Japan's government, and the centrally planned economy became one of the great economic success stories in history, going from a relatively primitive agrarian society to being able to beat Russia in a war by 1905. The Koban issues were the stamps that were in use during this rapid period of industrialization. There are many varieties, but it is the perforation types and the cancellations that most collectors find interesting.
As a sidelight, most countries make a considerable effort to integrate into the world. Japan is very willing to be part of the world economically, but culturally it retains its nationalist nature. This is seen in the fact that so few Japanese learn English in school and how relatively few study in the West and how few Westerners study in Japan. This is also seen in the difficulty in finding literature and information about Kobans and Koban varieties that is written in Western languages. One older Japanese stamp dealer who came to one of our specialized Japanese sales explained it to me by saying, "There are many very rare cancellations on these Koban issues that were only used on letters going overseas. If we publish information in English which let you learn about these cancels, we won't be able to buy the good ones at cheap prices ourselves."