The thirty-first gate of the House was not a portal meant for mortal coming and going.
It was the Barrier of White Jade, a massive flood-inner wall standing across the neck of Entry hall 325, separating the forty outer halls from the sacred inside vaults of the Tomb hall of Sovereign Memories. The twin leaves of the gate were carved from seamless giant pillars of white green jade eighty arm-lengths high and twenty arm-lengths thick, so dense and finely crystal-clear that their surfaces glowed with an internal, milky opalescence under the horn-lanterns. For ten thousand years, those stones had resisted the creeping moisture of the deep, untouched by salt-crust or barnacle scale.
The gate possessed no hinges, no bolts, and no locks of iron or bronze. Each leaf was suspended from an underground pivot of star-fallen iron six paces thick, balanced upon high-pressure balance weight chambers filled with eighty thousand gallons of liquid lead deep within the bedrock. The pressure between the outer and inner entry halls was in perfect water-pressure balance. Then, a child could push the twenty-thousand-ton jade leaves open with a single hand.
When the pressure was unbalanced, the gate became an unmoving cliff of stone that could withstand the impact of a falling mountain.
