Jörg Knappen wrote on Wed, May 5, 2010 08:37 AM UTC:
I don't think that the rook 'reappeared' in Shogi, because it was never gone. Makruk, one antecessor in the genealogical line of Shogi, also has it.
What is striking is that no widely played chess variant has lost the knight completely despite the fact that it is found difficult by many beginners and even intermediate level players of chess. The knight certainly adds 'flavour' to chess and to any chess variant where it is in.
The rook is another constant in chess, being there from the very beginning.