If classified by their shapes, koji used in Japan is in the shape of rice grain as it is, as far as can be observed by the naked eye, and, therefore, it is called bara koji (literally, loose koji).
また形状から分類すると、日本で用いられる麹は肉眼で見るかぎり米粒そのままの形をしているため、散麹（ばらこうじ）と呼ばれる。