Traditionally, the transactions are denominated in USD even if they do not involve a US counterpart. Since the Russian banks are forbidden to use SWIFT, you cannot pay or receive USD. How to solve the problem?

a) After a few weeks of sanction, the Russian government announced that for those rival nations, when they imported energy from Russia, they must settle the transaction by using Rubble. What kind of exchange rate risk hedging strategy did they use? Does it work? And Why?