Article 145(3) requires a minimum bench of 5 judges for cases involving substantial questions of constitutional interpretation or references under Article 143 (Presidential reference for advisory opinion). Regular cases need just 2-3 judges, but constitutional questions demand a larger bench for authoritative interpretation.

1. 1 Pick up Constitution.
2. 2 Go to Article 145(3).
3. 3 Read: 'The minimum number of Judges who are to sit for the purpose of deciding any case involving a substantial question of law as to the interpretation of this Constitution shall be five.'