Beneath the shallow waters of the Gulf, shared between Qatar and Iran, lies the North Field — the largest single natural gas reservoir on earth. The Qatari portion is developed. The Iranian portion, called South Pars, is partially developed and severely constrained by sanctions and investment restrictions. What happens to the gas that Qatar extracts from its side of the reservoir determines energy supply conditions for electricity consumers in Japan, industrial gas buyers in South Korea, and power generators across Europe. All of it moves through Hormuz.