Analysis: Jamie Robertson, BBC News

The gas deal between Russia and China was signed at 4 am China time, which gives some indication of the level of urgency over these talks. Mr Putin appears to have been determined not to leave Shanghai without a deal - and he got one.

But the financial details are a "commercial secret", so we don't know how much he had to give away to get it. Certainly China needs the gas to help it cut its coal-fired smog levels, and it wants to diversify supply. It had the luxury of time in which to negotiate, something Mr Putin was short of.

The perceived motive for the deal is that Russia needs a second market for its gas, so it can face up to European sanctions. Given that the "Power of Siberia" pipeline won't start pumping gas into Chinese factories until 2018 at the earliest, its economic effect on the European crisis will be limited.

More important may be the investment that China will make into Russia's power and transport infrastructure. Putin may not have managed to sign the most advantageous of gas deals on Wednesday but the opening of economic doors with China could well be the greater achievement.