  Based on the novel idea of twin-field quantum key distribution, we present a
sending-or-not-sending twin-field fault tolerant quantum key distribution
protocol. Our protocol can access a secure distance longer than 700 km even
though the misalignment error rate is $15\%$. In the case of zero alignment
error, our protocol can exceeds a secure distance of 800 km. Thanks to the
novel idea of TF-QKD !
