MAVO was a group of avant-garde artists active in Japan from 1923 to 1925. Led by Murayama Tomoyoshi who had just returned from studying in Germany, the group was heavily influenced by Constructivism, but the group also showed a tendency toward creating works intended to provoke and disturb by transgressing various boundaries, leading the group to be generally classified as "Dadaist" by art historians.
Members of the group referred to themselves as "MAVOists," and in addition to Murayama, included artists such as Yanase Masamu, Ogata Kamenosuke, Oura Shuzo, Kadowaki Kunio. Most of the group's works were installations, almost none of which survive, but the group was an important part of the avant-garde art movement in Japan in the early 1920s, which also included other short-lived art collectives such as Kanbara Tai's group "Action" and the "Third Section Society," or "Sanka" (which several of the MAVOists later joined).
If you really want to know everything there is to know about MAVO, there is a whole book on the group by Duke University art historian Gennifer Weisenfeld called Mavo: Japanese Artists and the Avant-Garde, 1905-1931.