On an April morning that President Donald Trump termed ‘liberation day’ for the US but left world markets to grapple with the tariff shocks from Washington, DC, a quieter but more consequential drama was unfolding in Beijing. China, on the brink of a trade war with the US, retaliated against the US’ reciprocal tariffs by announcing a slew of export restrictions on rare earth elements, essential inputs in the defence, energy and automotive sectors.