Why does that seem odd? It's an important waterway but passes directly through Istanbul. Like the Dardanelle straights these are contained inside Turkey. Un

Why does that seem odd? It's an important waterway but passes directly through Istanbul. Like the Dardanelle straights these are contained inside Turkey. Unfettered military transit would is an obvious problem for them, but pretty much everyone wants easy commercial traffic. Montreux is a pretty reasonable compromise. Note this control was taken away from the Ottoman empire as part of the treaty of Lausanne (i.e. fall out from WW1) but it wasn't surprising anyone when Turkey rejected the outcome.