"Nanakuchi no seki" refers to the checkpoints which were set on the seven roads leading to Kyoto from outlying regions (Kyoto nanakuchi, Kyoto's seven entrances) during medieval times.
七口の関（ななくちのせき）とは、中世に地方より京都に入る7つの街道（京都七口（きょうとななくち））に設置された関所のこと。