  We show that all quantum symmetric pair coideal subalgebras $B_\mathbf{c}$ of
Kac-Moody type have a bar involution for a suitable choice of parameters
$\mathbf{c}$. The proof relies on a generalized notion of quasi K-matrix. The
proof does not involve an explicit presentation of $B_\mathbf{c}$ in terms of
generators and relations.
