While
だが (or
ですが as a polite equivalent) are classified as their own words, they are actually just combinations of
だ, or
です, and
が.
だが is usually used as a formal way of saying ‘but’, or ‘nevertheless’. Due to this, we can see that
だ is being used to ‘determine’ that a statement is true, and then
が is simply showing that there is other important information to follow.
In this way,
だが is very similar to the expression ‘that may be, but…’ in English.
だが may be used at the beginning of any phrase, or between sentences.
-
彼（かれ）は弁護士（べんごし）だが、頭（あたま）が良（よ）くない、不思議（ふしぎ）だ。
He is a lawyer, but he is not very smart… Very strange.
-
宝（たから）くじを100枚（まい）かった。だが、当（あ）たらなかった。
I bought 100 lottery tickets. However, I did not win.
Caution - When using
ですが, it will automatically mean that the rest of the sentence should also use 丁寧語（ていねいご） (polite speech).
-
美容室（びようしつ）に行ったのですが、高（たか）かったので帰（かえ）りました。
I went to the hair salon, but since it was expensive, I went home.
To make
だが sound a little bit softer, sometimes
ね is added. However, this is not so common in modern-day Japanese, and is more limited to the older generation.
-
君（きみ）はいい人（ひと）だと聞（き）いた。だがね、まだ君（きみ）を信用（しんよう）できない。
I have heard that you are a good person. However, I can't trust you yet.
Fun-fact - Due to だが and ですが using が (the formal equivalent of けど), this phrase can sound quite stiff. Therefore, it is far more common to hear でも at the beginning of a sentence in casual speech.