Three Dragons is similar to ancient custodial capture board games such as Petteia, Tablut, Hnefatafl. However, it has two additional features as advanced variants of the base game:
1) Player pieces have strengths, so that a stronger piece can capture a weaker piece (in additional to traditional custodial capture), and
2)Three "dragon cave" spaces on the board allow players to obtain strong dragon pieces.
The base game is straight up custodial capture, with no strengths of pieces, and no dragons (but still the dragon cave spots in the center of the board to make things more interesting there).