  Spin squeezing (SS) is a recognized resource for realizing measurement
precision beyond the standard quantum limit $\propto 1/\sqrt{N}$. The
rudimentary one-axis twisting (OAT) interaction can facilitate SS and has been
realized in diverse experiments, but it cannot achieve extreme SS for precision
at Heisenberg limit $\propto 1/{N}$. Aided by deep reinforcement learning
(DRL), we discover size-independent universal rules for realizing nearly
extreme SS with OAT interaction using merely a handful of rotation pulses. More
specifically, only 6 pairs of pulses are required for up to $10^4$ particles,
while the time taken to reach extreme SS remains on the same order of the
optimal OAT squeezing time, which makes our scheme viable for experiments that
reported OAT squeezing. This study highlights the potential of DRL for
controlled quantum dynamics.
