とも details
write + let's + even if
kakou tomo
even if; no matter how — the literary concessive on the volitional and on the く-stem
meaning: even if you write
たとえ失敗しようとも、挑戦した事実は残る。
tatoe shippaishiyou tomo, chousen shita jijitsu wa nokoru.
The fact that you took it on remains, even if you fail. neutral
遅くとも来週の月曜までには結果が出ます。
osokutomo raishuu no getsuyou made ni wa kekka ga demasu.
The results will be out by Monday next week at the latest. neutral
- volitional
- i-adjective stem
Examples
even if; however much — the concession is granted at its extreme, and the main clause holds anyway
たとえ失敗しようとも、挑戦した事実は残る。
tatoe shippaishiyoutomo, chousen shita jijitsu wa nokoru.
The fact that you took it on remains, even if you fail. neutral
いかなる困難があろうとも、計画を最後までやり遂げる所存です。
ikanaru konnan ga arou tomo, keikaku o saigo made yaritogeru shozon desu.
Whatever difficulties may arise, we intend to see the plan through to the end. formal
どんなに厳しくとも、この条件だけは変えられない。
donna ni kibishiku tomo, kono jouken dake wa kaerarenai.
However harsh it may be, this one condition cannot be changed. neutral
少[すく]なくとも・遅[おそ]くとも — the frozen く-stem adverbs, "at least" and "at the latest"
遅くとも来週の月曜までには結果が出ます。
osokutomo raishuu no getsuyou made ni wa kekka ga demasu.
The results will be out by Monday next week at the latest. neutral
少なくとも三人は来るって言ってたよ。
sukunakutomo sannin wa kurutte itteta yo.
They said at least three people are coming. casual
Formation
{V-volitional}ともattaches to volitional{I-stem}くともattaches to i-adjective stem
Notes
have frozen into single adverbs and concede nothing — the productive
concessive reading typically pairs with たとえ・いかなる・どんなに in front.
Related patterns
Similar
One paradigm split by register — 高くとも and 高くても say the same thing, but とも is written-literary and pairs with いかなる・たとえ・どんなに, while ても is the everyday default; とも also refuses the て-form outright, riding the volitional instead (行こうとも, never ×行ってとも).
Both are written concessives, and they take different material — にせよ grants a whole proposition or a bare noun (冗談にせよ), while とも attaches only to the volitional or to an i-adjective stem, so it can never take a bare noun (×冗談とも).
Lookalikes
Both hang on the volitional plus と, so at the moment 〜（よ）うと is reached nothing is settled yet, and the next syllable settles it — も (or nothing) concedes and hands on to a main clause (どんな苦労があろうとも、続ける), while する narrates an attempt or an imminent event (立ち上がろうとする).