IFSC
India's eleven-character bank branch code, identifying exactly which branch a domestic transfer should reach.
The Indian Financial System Code is assigned by the Reserve Bank of India. The first four characters are letters identifying the bank, the fifth is always a zero reserved for future use, and the last six identify the branch. The code is required for transfers over NEFT, RTGS and IMPS, alongside an account number that has no common format across banks.
Pointing at a branch rather than just a bank reflects a system where the branch long held the account. Bank mergers have therefore triggered mass renumbering, with thousands of branches changing codes and customers having to update their payees. UPI has made the code invisible for most everyday payments, but it is still there underneath.