Last night after closing the short position for profit, I observed the K-line for a little while. It had already fallen off track. Usually, a sharp decline is followed by a rebound. After confirming stability, I opened a small long position near the support level. However, considering that during Christmas the foreigners are all celebrating, the market may lack sufficient liquidity to push through 0.618. So I locked in a more conservative position around Fibonacci 0.5, just right at 87,800 (although it's still 8U short).