Reasons for Chinese SM2 Digital Signature Algorithm

In the IETF RFC draft named "SM2 Digital Signature Algorithm" a signature algorithm is specified. The RFC does however not mention why this signature algorithm has been defined. Nor does it specify what the advantages of this scheme are over ECDSA. It seems that SM2 is the preferred EC signature format in China.

So the two related questions are:

1. Why was SM2 defined?
2. What are the (operational) differences compared to ECDSA?

Note that there seems to be a set of SM2 Elliptic Curve domain parameters defined as well.

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The IETF draft is a translation from a Chinese standard document, it seems. It also defines a key exchange protocol and an encryption algorithm. (I have no idea why it was defined, though.) –  Paŭlo Ebermann Aug 25 '13 at 12:32
Why? I guess because the chinese guys simply want to have their own standard (and I think being superior to existing schemes is not an issue ;) –  DrLecter Jul 31 '14 at 17:30
Part 1 (out of 4) of the 2010 Chinese standard defining SM2 algorithms is published here, and some of it is understandable when automatically translated. $\;$ Could no find part 2 on SM2 signature. $\;$ Jing Xu & Dengguo Feng's Comments on the SM2 Key Exchange Protocol is a claimed attack on part 3. –  fgrieu Aug 1 '14 at 3:51