  Let $(\bf U, \bf U^\imath)$ be a quasi-split quantum symmetric pair of
arbitrary Kac-Moody type, where "quasi-split" means the corresponding Satake
diagram contains no black node. We give a presentation of the $\imath$quantum
group $\bf U^\imath$ with explicit $\imath$Serre relations. The verification of
new $\imath$Serre relations is reduced to some new q-binomial identities.
Consequently, $\bf U^\imath$ is shown to admit a bar involution under suitable
conditions on the parameters.
