Nare-zushi (described as 馴れ寿司 or 熟寿司 in Japanese) refers to sushi made through processes of mixing fish with salt and rice, preserving it for a long time and fermenting it by the action of lactbacillus.
なれずし（馴れ寿司、熟寿司）は魚に塩と飯を混ぜて長期間保存し乳酸菌の作用によって発酵させたもの。