  We define the virtual bridge number $vb(K)$ and the virtual unknotting number
$vu(K)$ invariants for virtual knots. For ordinary knots $K$ they are closely
related to the bridge number $b(K)$ and the unknotting number $u(K)$ and we
have $vu(K)\leq u(K), vb(K)\leq b(K).$
  There are no ordinary knots $K$ with $b(K)=1.$ We show there are infinitely
many homotopy classes of virtual knots each of which contains infinitely many
isotopy classes of $K$ with $vb(K)=1.$ In fact for each $i\in \N$ there exists
$K$ virtually homotopic (but not virtually isotopic) to the unknot with
$vb(K)=1$ and $vu(K)=i.$
