Tense and aspect markers in Japanese relative clauses contrast with each other in unique ways not observed in matrix sentences. Different kinds of semantic contrasts appear under particular conditions, depending on whether the relative clause and matrix sentence verbal phrases represent actions vs. states, or are habitual vs. non-habitual. When verbal phrases of both the relative clause and the matrix sentence name non-habitual past actions, the occurrence of relative-clause-final -ta, -te iru, and -te ita can be explained in terms of the opposition simultaneous vs. non-simultaneous. Comparison of examples with verbal phrases of stative non-habitual matrix sentences leads to the formulation of a ‘principle of convergence’, which is later extended to other cases. When the verbal phrase of a relative clause designates a habitual past action, relative-clause-final verbal forms in -ru, -ta, and -te ita all occur, but these forms connote varying degrees of randomness, two of which are contrasted in detail as the ‘true habitual’ vs. ‘iterative’ usage.