Tsumego (life and death) GAME
Four grades: Beginning, Elementary, Intermediate, Advanced.
A lot of types: Atari , Live, Nakade, Ko, Capturing race, Throw-in, Net, Clamp, Connect along the edge, Ladder, Cut, Hane, Wedge ,Kosumi, Jump, Sagari, Placement, Two-stone edge squeeze, Double shortage of liberties, Under the Stones, seki , Vital point , Go Theory , Corner Shapes, Eyes win, Tesuji, Endgame,Atari.