line.

The peculiarities of the IRIS observations are many-fold: first, the spectrograph’s slit was positioned exactly over the plage flare ribbon, and intersected, among others, the strongest kernel within the whole flare (as observed in the SJIs). Second, the ribbon developed rapidly [*along*]{} the slit, providing multiple, independent instances of elementary flaring kernels (see Paper I for a more thourogh discussion). Third, the observations started well before the initiation of the flare, thus capturing the evolution of any given flaring area from their earliest moments. This is a very rare occurrence. Fourth, the 9.4 s cadence is among the highest ever achieved for UV flare spectra, and allows novel analyses of the rapidly evolving chromospheric condensation. Finally, the strongest flaring kernels were so intense that many weak chromospheric lines clearly turned into emission, providing a range of complementary diagnostics beside the most-often used Mg [ii]{} and C [ii]{} lines.

Figure \[fig:irisaia\] shows the flare’s ribbons at the time of maximum chromospheric emission, as determined from the 2796 Å SJIs. The most intense brightening in the IRIS images is highlighted by a pink contour on the simultaneous AIA 1600 Å  image; at this time the kernel was at maximum brightness and 