Later on, however, due to the collapse of the handensei (state controlled land allotment system), the increase of iden (fields allotted according to court rank) and Kokushi (provincial governors) converting jishi to shozei (rice taxed by provincial offices), the number of joden, which were essentially the extra fields of handen (allotted fields), were gradually decreased along with their jishi.
だが、後に班田制の崩壊と位田などの増加、国司による地子の正税などへの転用によって本来は班田の余剰田であった乗田及びその地子も減少するようになった。