In Shad Yantra, which later became Chess. Rules were purely based on Categories.
Royals: Raaja means King and Deputy of King called Mantri
Immortal: Guru or Peace Ambassador.
Army Commandar: General or Queen.
3 level of Officers.
Pawns as common solidiers..
Pawns are non autononous and resource. They are also on 0 level, hence pawns cannot move on their own. They can move only as per the neighbouring Senior Rank Officer.
All Officers and King are autonomous units Hence they can move 1 step only. Hence, when Officers are in touch with Army General, or Royal King or Royal Mantri (Deputy of King) these officers can move additional steps as per their level. This is called elevated move.
Bishop or Elephant Unit are on 1st level. So bishop gets 1 extra step (2 in total) in any direction when Elevated.
Knight is on 1.50 level. So Knight gets 1.5 extra step (2.5) in total when elevated.
Rook is on 2.00 level. So elevated Rook gets extra 2 steps (3 in total) l.
Army General or Queen is on 2.5 level. Elevated Army General gets extra 2.5 steps. (3.5) steps in total.
King and Mantri are on 3.5th level. Elevated King can move 4.5 in total.
King is the most powerfull of all pieces, but in modern chess King moves 1 step only.
Default moves of all units is 1 except pawns...