The gold standard system takes gold as the final monetary unit of final settlement, which is hard currency. This problem belongs to the category of international finance and international settlement. At that time, the foreign exchange reserves of various countries were pounds and gold. Then at that time, the currencies of all countries were linked to gold in international settlement, and gold was linked to pound, so the gold standard system at that time was a system based on the pound price of century gold. Even today, the exchange rate of the pound must be reviewed.

The Bretton Woods system is that after the United States became the world's largest creditor country after the war, Britain lost its financial dominance, the pound could no longer be linked to gold, and the dollar became the first settlement tool. So our current foreign exchange reserves are US dollars. In other words, the Bretton Woods system is the dominant position of the United States in world trade and finance, which overthrew the gold standard linked to the pound and gold.

If you need to know more, I suggest you find a book on the basics of monetary finance or monetary science, which has been discussed in detail. As for the currency war, look at fantasy novel.