So, which is which with それで
Grammar Explanation: The reason or result with それで

Mina tells Sanae that if you clasp your hands together, you can know whether you were a boy or a girl in a past life. When Mina interlocks her fingers, her left thumb is on top. For Sanae, it’s her right thumb. In the past, one was a boy, and the other was a girl.
- サナエ:
- 「それで、どっちがどっちなの?」
- “So, which is which?”
Key Points
それで moves from setup to result
Here それで means “so” or “and then, as a result”.
Sanae is asking for the actual conclusion after hearing Mina’s explanation about past-life hand-clasping.
どっちがどっち = “which one is which”
This asks how two options map onto two outcomes.
In context, Sanae wants to know which hand position means “boy” and which means “girl”.
が marks the item to be identified
“どっちが” sets up the unknown item whose identity or role is being sorted out.
The sentence is essentially asking: “So, which one corresponds to which result?”