In case of white closing Marubozu,the close price is the highest price of that underlying stock for that session,however open price is not the lowest price.
This means that, there were many market participants ready to buy the underlying stock at any price during the session and due to this high demand the price kept on increasing and closed at the highest point for that session, however during this session there was a time when seller emerged and price dipped below the open price for a brief moment but buyer took control eventually.
If you think for a moment, closing white Marubozu feels stronger than Bullish Marubozu. Reason being even though sellers tried to push price lower,buyer still able to close at the highest price point during the session.
Decision: In case of white closing Marubozu,traders should start looking for buying opportunities, buy price should be around the closing price of white closing Marubozu.
Stop loss: What if the market reverse its direction after printing the white closing Marubozu ? The low of the candle will act as stop-loss in case that happen.