Japanese kanji provides a stimulus-rich environment for research in the perceptual and cognitive processes required for reading, memory, and language acquisition in general. However, in order to do research on perceptual and cognitive processing using kanji, it is important to have a good understanding of the several potentially important differences between the Japanese writing system and other writing systems.The first difference between the Japanese writing system and others is that three different scripts are used in Japanese: kanji, hiragana, and katakana. Kanji originally developed from pictographs used by the Chinese thousands of years ago to represent objects and events in the world around them. Some of these kanji have retained their pictographic forms and remain similar in appearance to the objects that they were intended to represent. Those kanji-such as , meaning forest, , meaning gate, and , meaning storage-that have maintained their pictographic image well in the process of script development may be easier for nonnative Japanese learners to acquire by using an imagery mediation strategy, as was indicated by Kuwabara (2000). Later on, other kanji were formed to represent more abstract ideas, whereas still others developed using combinations of single characters that convey information about a related idea. A fourth type of kanji consists of elements that are related to pronunciation. Hiragana and katakana are scripts representing morae (slightly smaller units within syllables) to depict the same set of 46 basic sounds. Hiragana is used for grammatical inflections and words where the writing of kanji is avoided. Katakana is used to write words and names that are not of Japanese or Chinese origin. No further consideration will be given to hiragana and katakana in this paper or in the associated database.The second important difference between the Japanese writing system and others found in the world has to do with the number of basic kanji characters. In the version of kanji now in common use, there is a total of 1,945 basic characters. The difficulty associated with the mastery of this large set of characters is evident in the way the pedagogic load must be spread out over the first 9 years of schooling.The authors thank Shoichi Yokoyama and Sanseido (publishing company) for allowing the use of the kanji frequency data from Yokoyama, Sasahara, Nozaki, and Long (1998). In addition, much gratitude is given to the reviewer, Yasushi Hino, as well as to an anonymous reviewer of this paper, for their valuable suggestions. Correspondence concerning this article should be addressed to K. Tamaoka, International Student Center, Hiroshima University, 1-1, 1-chome, Kagamiyama, Higashihiroshima, Japan 739-8523 (e-mail: ktamaoka@hiroshima-u.ac.jp). In 1981, the Japanese government published a list of the 1,945 basic Japanese kanji (Jooyoo Kanjihyo), including specifications of pronunciation. This list was established as the standard for kanji usage in print. The database for 1,945 basic Japanese kanji provides 30 ...
