158 checkout: T20 T20 D19

Recommended route

3 darts, finishes on D19

T20 T20 scores 120 and leaves 38 on D19.

There's no safety net: a single 20 with the first dart leaves 138, which two darts can't finish.

D19 is an odd double: a single 19 leaves 19, an odd number that needs another setup dart.

Knowing the route for 158 is one thing. Seeing it in a second, with the clock running, is what Dartel trains.