In early times, "kamei" were written predominantly in hiragana. After the invasion of the Ryūkyū Kingdom by Japan's Satsuma Domain in 1609, the Japanese-style use of Chinese characters (kanji) was adopted. The Keichō Land Surveys of 1609-1611 probably conventionalized to some degree the choice of kanji for place names, and thus surnames based on them. In 1625 the Satsuma Domain instituted a . As a result, the kanji used to write "kamei" changed from characters that were common in Japan to new, unique character combinations. For example, the name 東 (Higashi) was often changed to 比嘉 (Figa) or 比謝 (Fija), the name 前田 (Maeda) to 真栄田 (the same reading), 福山 (Fukuyama) to 譜久山 (the same reading), etc.