  We present first results of UT1-UTC determinations using the VLBI Global
Observing System (VGOS). During December 2019 through February 2020 a series of
1~hour long observing sessions were performed using the VGOS stations at
Ishioka in Japan and the Onsala twin telescopes in Sweden. The data of this
VGOS-B series were correlated, post-correlation processed, and analysed at the
Onsala Space Observatory. The derived UT1-UTC results were compared to
corresponding results from standard legacy S/X Intensive sessions (INT1/INT2),
as well to the final values of the International Earth Rotation and Reference
Frame Service (IERS), provided in IERS Bulletin~B. The VGOS-B series achieve
3-4 times lower formal uncertainties for the UT1-UTC results than standard
legacy S/X INT series. Furthermore, the root mean square (RMS) agreement with
respect to the IERS Bulletin~B is 30-40 % better for the VGOS-B results than
for the INT1/INT2 results.
