nunca

Nunca follows the same double-negation rule as nada: it can either precede the verb with no "no" ("Nunca llego tarde") or follow the verb with "no" before it ("No llego nunca tarde"). Both patterns are grammatically correct; placing nunca before the verb for emphasis is slightly more formal.

Nunca and jamás are near-synonyms but not perfectly interchangeable. Jamás is more emphatic and literary; "nunca jamás" (never ever) is the intensified collocation. In affirmative questions and conditional sentences, both can mean "ever": "¿Has estado alguna vez en Japón?" is more common than "¿Has estado nunca en Japón?" though both are used.