Kage

Kage is a 1986 game by Jay Myers, published by TSR. 

The game, played on a 8x8 board, comes with one red 'bird', one blue 'bird', and 48 white walls.

The rules:

• Initially, the birds are placed at d5 and e4
  
• Then, on his turn, a player can either:
• Move his bird to an orthogonal adjacent empty square (if there's no wall in-between)
• Drop a wall in-between squares, or at the board's edge
  
• Wins the player that encloses the adversary bird in a connect chain of walls (the cage), 
• Note that the edge itself is not a wall; if the cage includes the board edge, then those squares also need walls.
  
• The player wins even if his own bird gets enclosed at that same turn
• If after placing all walls, neither bird is enclosed, the game is a draw
  

Some tips from Chris Okasaki:

Be sure to pay attention to how your opponent can use the toothpicks you place against you. This is especially true in the endgame, where it is common to see one player place a toothpick intending to threaten the other pawn, and then the other player suddenly wins by placing a toothpick that encloses both pawns simultaneously.

An advanced tactic is to use your pawn to block your opponent from escaping your enclosure. It is dangerous, however, because to do so you must be close enough to risk being enclosed yourself.