Some notes on the Kruskal–Szekeres completion

The Kruskal–Szekeres (KS) completion of the Schwarzschild spacetime is open to Synge's methodological criticism that the KS procedure generates ‘good’ coordinates from ‘bad’. This is addressed here in two ways: first I generate the KS coordinates from Israel coordinates, which are also ‘good’, and then I generate the KS coordinates directly from a streamlined integration of the Einstein equations.