にしても

1. 1Even though X is true (granting it), the speaker still holds a contrary judgment.Ex. 1
2. 2Even if it is (supposed to be) X, what follows still applies.Ex. 2
3. 3In the paired form AにしてもBにしても, the same holds whether it is A or B.

Used in both conversation and writing. The main clause usually gives the speaker's opinion, evaluation, request or complaint that runs against what the first part implies. It is more neutral than the stiffer にしろ/にせよ and less casual than にしたって.

• にしろ / にせよN2「にしろ」 and 「にせよ」 are essentially the same as 「にしても」 in both their concessive use and their paired use as 「AにしろBにしろ」, and are often interchangeable with it. The difference is register: 「にしても」 is plainer, 「にしろ」 is also common in speech, and 「にせよ」 is more written and stiff.
• にしたってN1「にしたって」 is the colloquial form of 「にしても」, with essentially the same concessive meaning, and the two are interchangeable in everyday conversation. It sounds more casual, however, and is unsuitable for formal writing; attached after a personal noun, it often carries the nuance of 'even that person'.
• としてもN2「としても」 leans toward treating the first clause as a hypothesis and often pairs with 「たとえ」 or 「仮に」. After nouns and な-adjectives, 「だ」 is generally added, as in 「学生だとしても」, though after nouns it is sometimes omitted, as in 「それが事実としても」.
• としたって / としたところでN1「としたって」 and 「としたところで」 lean colloquial and center on supposition, with the second clause typically a negative judgment that the outcome will not change and the effort is wasted. When supposing, nouns and な-adjectives add 「だ」 before attaching; when expressing a stance, a personal noun attaches directly, making the pattern close to 「にしても」.
• といえどもN1「といえども」 is close in concessive meaning but solemn in tone, appearing mostly in written language, speeches, or regulations, and it emphasizes that even a certain status, an extreme condition, or a minimal amount like 「一円」 is no exception. In everyday conversation it sounds stiff.
• だってN2Attached to a noun, 「だって」 means 'even ... too' and leans colloquial; 「にしても」 attaches more widely, conceding the first clause before offering an evaluation or complaint, with a neutral register. 「だって」 can also open a sentence to justify oneself, a use 「にしても」 does not have.

にしろ/にせよ are stiffer, more written equivalents, while にしたって and だって are casual spoken counterparts. としても puts more weight on a purely hypothetical assumption, as does its casual form としたって; としたところで often adds that the supposed case would make no difference, and といえども is formal and literary.