  The recently reported observation of VFTS 243 is the first example of a
massive black-hole binary system with negligible binary interaction following
black-hole formation. The black-hole mass ($\approx 10\ M_{\odot}$) and
near-circular orbit ($e\approx 0.02$) of VFTS 243 suggest that the progenitor
star experienced complete collapse, with energy-momentum being lost
predominantly through neutrinos. VFTS 243 enables us to constrain the natal
kick and neutrino-emission asymmetry during black-hole formation. At 68% C.L.,
the natal kick velocity (mass decrement) is $\lesssim 10$ km/s ($\lesssim 1.0\
M_{\odot}$), with a full probability distribution that peaks when $\approx 0.3\
M_{\odot}$ were ejected, presumably in neutrinos, and the black hole
experienced a natal kick of $4$ km/s. The neutrino-emission asymmetry is
$\lesssim 4$%, with best fit values of $\sim$0-0.2%. Such a small neutrino
natal kick accompanying black-hole formation is in agreement with theoretical
predictions.
