A flag with a hole in it

One colour has been painted out of a country’s flag and replaced with grey. Four colour swatches are offered; pick the one that belongs, and the real flag is revealed. Ten flags make a round, and the flags you have already been asked are set aside so the next round brings new ones.

Which colour goes missing

The level decides which colour is removed, not just which flags are asked. Easy takes out the flag’s biggest colour, from the 100 best-known countries; Medium the second-biggest, from 150 countries; Hard the third, from all 195, which is often the thin stripe or the emblem you had never looked at. The flag is analysed on the spot, so a round may take a moment to prepare.

Grey is never the hidden colour, and black is a fair answer: Germany, Belgium, Estonia and many Arab and African flags use it.