The art of arranging flowers, called ikebana, is an aesthetic attainment unique to the Japanese people. Although the exact origin of this art is unknown, people have arranged flowers and tree branches for Shinto and Buddhism altars since ancient times. Documents record that arranging flowers for rooms became popular during the Muromachi period. Afterwards, chiefly during the Edo period, many schools sprang up and various methods of arranging flowers developed. Today there are more than 300 different schools (2016). There are many styles, also, but the best-known style of flower arrangement is perhaps the “heaven-earth-man” style. All the schools can be divided into two principal types: the formal school and the natural school.