There are two methods. One shifts only the rates to earlier business days and keeps the day weights of the interest period (without an observation shift). The other shifts the whole observation period earlier and uses the day weights of the shifted period (with an observation shift).
For Japanese yen loans, the loan subgroup of the Cross-Industry Committee on Japanese Yen Interest Rate Benchmarks based its work on the method without an observation shift, and in its consultation a large majority supported presenting five business days as an example.