As can be seen from the adjacent chart, MCX copper tumbled down in a channelised manner. The third leg of the fall has reached the lower channel line. The base metal has also tested a medium-term rising trend line. At these crucial supports, the red metal has formed a bullish outside bar. Thus, the low of the bullish bar (391.80) will act as a key support on a closing basis. The daily momentum indicator is looking for a recovery from the oversold zone. Thus, from the short-term perspective copper can move up till 420.