  A new intrinsic-colour calibration ($(b$--$y)_{o}$--$\beta$) is presented for
the $uvby$--$\beta$ photometric system, making use of re-calibrated Hipparcos
parallaxes and published reddening maps. This new calibration for
$(b$--$y)_{o}$--$\beta$, our Equation (1), has been based upon stars with
$d_{Hip} < 70$ pc in the photometric catalogues of Schuster et al. (1988, 1993,
2006), provides a small dispersion, $\pm0.009$, and has a positive ``standard''
$+2.239\Delta\beta$ coefficient, which is not too different from the
coefficients of Crawford (+1.11; 1975a) and of Olsen (+1.34; 1988). For 61
stars with spectra from CASPEC, UVES/VLT, and FIES/NOT databases, without
detectable Na I lines, the average reddening value $<E(b-y) > = -0.001\pm0.002$
shows that any zero-point correction to our intrinsic-colour equation must be
minuscule.
