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Basically what it says on the tin. Rules and conditions of the challenge:
1. POD must be after 1000 AD.
2. No ASB or improbable technological advances.
3. Be reasonable in terms of luck allotment (eg: a horde avoiding an OTL succession crisis is fine, avoiding 10 succession crises is ridiculous).
4. Siberian steppe states or aboriginal tribes grossly controlling Siberia will fulfill this challenge IF said polities are integrated into the Eurasian international system (as opposed to being isolated and/or undiscovered).
5. The chosen power or culture must be able to plausibly survive beyond 1900. Endogenous successor states (eg Revolutionary France out of the French Kingdom), will fulfill this condition. Exogenous successor states (eg the Mughal Empire) will fulfill this condition if the progenitor is not Russia.