そういえば

Literally 'if (one) says so' — そう (so/that way) + 言(い)えば (if one says). Used when the current topic prompts the speaker to recall something related. The follow-up is usually loosely connected to what was just said.

Common patterns

• Sentence-initial only, followed by a comma.
• Often paired with けど or んだけど before stating the new point.

Common collocations

• そういえば、昔(むかし)…: come to think of it, in the old days …
• そういえば、聞(き)いた?: speaking of which, did you hear?
• そういえば、そうだね: oh yeah, that's true (when reminded of something)

Similar words

• ところで: by the way (deliberate topic change, not necessarily reminded by context)
• それはそうと: by the way; that aside (more deliberate shift away from current topic)
• ちなみに: incidentally; for your information (adds related info)