An established theory for the origin of charyo is that the utensil was designed by Baisao (a monk of Obakushu sect) in the middle of the Edo period for convenience of measuring and pouring in of tea leaves.
江戸時代中期、売茶翁が茶葉の量と投入の便宜のためにこの道具を考案したというのが定説となっている。