Japanese
Conjugation
Forms
Dictionary
Base form, listed in dictionaries. Plain affirmative present.
Polite 〜ます
Neutral-polite present. The 〜ます stem feeds many other forms.
Negative 〜ない
Plain "doesn't / won't". Conjugates like an い-adjective.
Negative polite 〜ません
Polite negative.
Past 〜た
Plain past. Same stem rules as the て-form.
Past polite 〜ました
Polite past.
Past negative 〜なかった
Plain "didn't". 〜ませんでした for polite.
て-form
Connective: requests, linking clauses, continuous (〜ている). The key form.
Full conjugation overview on Wikipedia.