〜ことは〜が details

write + I do X, yes, but — the word itself is granted, and the objection follows

kaku kotoha kaku ga

I do X, yes, but — the word itself is granted, and the objection follows

meaning: do write, but

行くいくことは行くがことはいくが、あまり気きは進すすまない。

iku kotoha iku ga, amari ki wa susumanai.

I do go, but I'm not keen on it. neutral

おいしいことはおいしいけど、ちょっと高たかいよね。

oishii koto wa oishii kedo, chotto takai yo ne.

It's tasty all right, but it is a bit pricey, isn't it. casual

dictionary form
た-form
i-adjective
na-adjective
colloquial
alternant

Examples

I do X, all right, but — the speaker grants the very predicate at issue before qualifying it

行いくことは行いくが、あまり気きは進すすまない。

ikukotohaikuga, amari ki wa susumanai.

I do go, but I'm not keen on it. neutral

おいしいことはおいしいけど、ちょっと高たかいよね。

oishii koto wa oishii kedo, chotto takai yo ne.

It's tasty all right, but it is a bit pricey, isn't it. casual

説明せつめいを聞きくことは聞ききましたが、正直しょうじきよく分わかりませんでした。

setsumei o kiku koto wa kikimashita ga, shoujiki yoku wakarimasen deshita.

I did listen to the explanation, but honestly I didn't really follow it. neutral

読よんだことは読よんだが、内容ないようはもう覚おぼえていない。

yonda koto wa yonda ga, naiyou wa mou oboete inai.

I did read it, but I no longer remember what was in it. neutral

このアプリは便利べんりなことは便利べんりだが、電池でんちの減へりが早はやい。

kono apuri wa benri na koto wa benri da ga, denchi no heri ga hayai.

This app is handy enough, but the battery drains fast. neutral

検討けんとうすることはいたしましたが、今回こんかいは見送みおくらせていただきます。

kentou suru koto wa itashimashita ga, konkai wa miokurasete itadakimasu.

We did give it consideration, but on this occasion we will pass. formal

Formation

{V}ことは{V}がattaches to dictionary form
{V-ta}ことは{V-ta}がattaches to た-form
{I}ことは{I}がattaches to i-adjective
{NA-stem}なことは{NA-stem}だがattaches to na-adjective

Variant notes

ことは〜けど — the spoken tail — が gives way to けど in conversation (おいしいことはおいしいけど、高たかい).
ことは〜けれども — the unclipped form — が is the written default, けれども the careful spoken middle between it and けど.

Notes

Both copies are the same word, and only the second inflects — politeness and
keigo included (聞きくことは聞ききました, 検討けんとうすることはいたしました).
Past alone may be echoed on both: 読よんだことは読よんだが。

Related patterns

Similar

けど
けど concedes a whole clause and moves on; ことは〜が narrows the concession to a single word by repeating it, so the listener knows exactly which part is being granted and which part the objection is about to attack.
が
The が here IS the contrastive が, with the concession built in front of it — plain 〜が opposes two different facts (安やすいが、質しつが悪わるい), while ことは〜が first admits the very word the objection will qualify (安やすいことは安やすいが).
ものの
ものの is written register and concedes a fact that turned out not to matter; ことは〜が is spoken-first, repeats one word, and always sets up the speaker's own reservation about that same word.

Lookalikes

たことがある
The た row walks straight into it — 行いったことは… sets up the experiential 行いったことがある, and only the repeated verb (行いったことは行いった) tells the reader that a concession, not a life experience, is being reported.
ことはない
Same 〜ことは opening, unrelated grammar — ことはない denies NECESSITY with one verb and stops there (謝あやまることはない), while ことは〜が repeats the verb and concedes it; reading only as far as ことは leaves the two indistinguishable.