In Japanese, the katakana script is usually used for foreign loan words, foreign proper nouns, and onomatopoeia. However, katakana is occasionally used to represent words of Japanese origin. In one case, the word karada is written in katakana on a Japanese magazine. Karada is a Japanese word that means "body". It is difficult to understand why karada is written in katakana rather than kanji or hiragana. It may have been written this way in order to add emphasis. Katakana adds emphasis because katakana characters usually have much harder corners and angles than hiragana or kanji. These characters tend to stand out. The magazine is a fitness magazine, therefore it would make sense to emphasize the number one topic of fitness; the human body. This all achieves the effect that when you look at the magazine the first thing that you see is karada.
Japanese Military transmissions are also written in katakana even though they often use words of Japanese origin. For example, when someone in the Japanese military wants to tell someone to halt, they send the word "toma" written in katakana. This is surprising because toma is actually short for tomaru, the japanese word for halt and it one would expect it to be written in hiragana. This is likely because katakana characters are more simple than hiragana. In a situation where something must be written quickly, it would make sense to use katakana.
Most textbooks briefly explain katakana, hiragana, and kanji in a few short paragraphs. For the most part, katakana is described as a form of writing identical to katakana and used for foreign words. While this description is true, it also leaves out some of the more subtle uses of the script. It makes sense that a textbook would want to keep a description of the writing system brief as this is arguably one of the most daunting parts of Japanese at first. However, not emphasizing katakana can make Japanese more difficult down the road when a student realizes the other ways in which it can be used.
