Nenkiho is also called '20-year Nenkiho' since the 'twenty-year chigyo (enfeoffment)' principle having 20-year enfeoffment (exercise of rights of possession/occupation) as its requirement of realization was introduced after the enactment of the Goseibai-shikimoku (code of conduct for samurai).
御成敗式目以後、20年間の知行（所有・占有の権限行使）を成立要件とする「廿箇年知行」原則が導入されたことから、「二十箇年年紀法」とも呼ばれる。