As described above, the Branch Library System across the three powers is extremely rare among the national libraries of the world, and it is regarded as one of the most prominent characteristics of the NDL.
このように三権をまたぐ支部図書館制度は世界の国立図書館の中でもきわめて珍しく、国立国会図書館のもつ大きな特色のひとつである。