研ぐ (togu) conjugation
to sharpen, to grind, to polish
研ぐ (とぐ, togu) is a godan verb. Godan verbs change their final kana up and down its column of the kana chart — the a-row for negatives, the i-row before ます, the e-row for potential and ば. Every form below is tappable — hear it, then say it back.
Conjugation table
| Form | Plain (casual) | Polite (~ます) | When you use it |
|---|---|---|---|
| Dictionary / plain | 研ぐ togu | 研ぎます togimasu | The form you look up. Also the casual present and future. |
| Plain negative | 研がない toganai | 研ぎません togimasen | “doesn’t / won’t”. From here it conjugates like an i-adjective. |
| Plain past | 研いだ toida | 研ぎました togimashita | The casual past — same ending as the te-form, with た/だ. |
| Plain past negative | 研がなかった toganakatta | 研ぎませんでした togimasendeshita | “didn’t”. The negative past, still i-adjective-shaped. |
| Te-form | 研いで toide | — | The connector: requests, linking clauses, ~ている. |
| Progressive (~ている) | 研いでいる toideiru | 研いでいます toideimasu | “is ~ing”, or an ongoing resulting state. |
| Desire (~たい) | 研ぎたい togitai | 研ぎたいです togitaidesu | “want to ~”. Behaves as an i-adjective. |
| Volitional | 研ごう togou | 研ぎましょう togimashou | “let’s ~” / “I think I’ll ~”. |
| Potential | 研げる togeru | 研げます togemasu | “can ~”. What you could do; the object often takes が. |
| Passive | 研がれる togareru | 研がれます togaremasu | “is ~ed”. Also the honorific and the suffering passive. |
| Causative | 研がせる togaseru | 研がせます togasemasu | Make or let someone do it. |
| Causative-passive | 研がされる togasareru | 研がされます togasaremasu | Be made to do it — the long one. |
| Imperative | 研げ toge | 研いでください toidekudasai | Blunt order. Use ~てください in real life. |
| Prohibitive | 研ぐな toguna | — | “don’t!” — dictionary form + な. |
| Conditional (~ば) | 研げば togeba | — | “if ~”. General rules and hypotheticals. |
| Conditional (~たら) | 研いだら toidara | — | “if / when ~”. The everyday conditional. |
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Why it conjugates this way
Godan verbs change their final kana up and down its column of the kana chart — the a-row for negatives, the i-row before ます, the e-row for potential and ば.
See the full rules on the verb conjugation guide.