FOUR OF THE five priciest transfers in European football this summer involved England’s cash-soaked Premier League. The fifth was more unusual. Victor Osimhen, a Nigerian striker, left Napoli, the Italian champions, for Galatasaray in Turkey’s Super Lig. The €75m ($87m) transfer fee was the biggest in Turkish history, more than triple the old record. Mr Osimhen will earn €15m a year after taxes, comparable to top players in England and Spain. Nor was it a one-off. Galatasaray and their crosstown rivals, Fenerbahce and Besiktas, have signed loan deals for high-profile players from Europe and even Saudi Arabia. Continental clubs are tightening belts. What is happening in Istanbul?