const oppCol = C.GetOppCol(color);
if (this.options["balance"] && [1, 3].includes(this.movesCount)) {
// Forbid moves either giving check or exploding opponent's king:
const oppCol = C.GetOppCol(color);
if (this.options["balance"] && [1, 3].includes(this.movesCount)) {
// Forbid moves either giving check or exploding opponent's king: