Beijing, April 29 - The Chinese yuan strengthened 9 basis points to 6.1556 against the US dollar Tuesday, according to the China Foreign Exchange Trading System.

In China's foreign exchange spot market, the yuan is allowed to rise or fall by 2 percent from the central parity rate each trading day, reported Xinhua.

The central parity rate of the yuan against the US dollar is based on a weighted average of prices offered by market makers before the opening of the interbank market each business day. (IANS)