Granular herbicides have been used for the past 40 years in Japan and account for 86% of all rice herbicides applied. They are packed in 3 kg packages as a 0.1 ha dose on the assumption that they will be used in hand treatment like fertilizers. Trials have been carried out to minimize application labour in paddy fields. In one of them, flowable herbicides were developed in 1986 and the merit of easy application without use of tools was recognized. Another trial was made to reduce the dosage of granular herbicides from 3 kg/0.1 ha to 1 kg/0.1 ha. In yet another, The Japan Association for Advancement of Phyto-Regulators (JAPR) has carried out basic research on large granular type herbicide, provisionally called Throw-in type formulation (so called "Jumbo" formulation), in an attempt to treat 0.3 ha paddy fields within 5-6 min. by throwing "Jumbo" from levees into the field. "Jumbo" application does not require any particular equipment and is labour saving.