ただし
However, provided that (adds a condition or exception)machine translation
FormationAt the start of the following sentence: Sentence A。ただし、sentence B。
ただし adds a CONDITION or EXCEPTION to what was just affirmed: 入場は無料です。ただし、飲み物は有料です (admission is free. However, drinks cost money). Sentence A remains entirely true — ただし merely pencils in a "note" beside it.
This is the signature word of rules, notices, contracts, and exams — wherever there's a ※ mark, ただし is almost sure to be nearby. It also works in polite speech when you need to state a limitation up front.
Distinguishing it from the other "but" words: しかし・でも express contrast and can overturn the previous statement; ところが announces a result contrary to expectation. ただし contradicts NOTHING at all — it keeps sentence A intact and only attaches conditions of application. That's why sentences with ただし always carry the structure "main rule + footnote."
Examples
入場は無料です。ただし、飲み物は有料です。
Admission is free. However, drinks must be paid for.
明日はテストをします。ただし、辞書を使ってもいいです。
There will be a test tomorrow. However, you may use a dictionary.
このプールは誰でも利用できます。ただし、子供は大人と一緒に入ってください。
Anyone can use this pool. However, children must enter together with an adult.