It's basically a shogi-style game, with a 4x4 palace and river like in xiangqi, where the king can summon 16 different types of pieces — up to 16 times each — so he has a "deck" of around 200 pieces to summon from. You get two actions per turn, which can be any combination: two summons, two moves, one move and one summon, or an attack and a summon, or a move and an attack.

The king can only summon pieces while inside the palace. If he's outside the palace, he can instead charge up a spell to kill an enemy piece that has crossed the central river.

However, each piece is actually a card from a TCG featuring anime isekai girls, each one inspired by one of 16 historical empires.