evidence: Iraqi maps of the region show Iraqi territory in pale gray and Iran in dark gray. But a large zone, corresponding roughly to the Iranian province of Khuzistan (or Arabistan as it is termed in Iraq), is marked out separately in alternating shades of gray. With a population of ethnic (and linguistic) Arab stock that has coexisted uneasily with the Iranian majority of the country, the area has been a battleground for ambitious regional potentates since ancient times. The Shatt al Arab river is both a natural border line for Khuzistan, between modern Iraq and Iran, and a strategically vital means of access for the cities on both sides. For Iraq, the Shatt al Arab is only one of its geographic vulnerabilities in the area. Another feature of the map is that, between Fao and Umm Qasr, Iraq has less than 50 miles of coastline on the Gulf-most of it unusable for shipping. The main port, Basra, is nearly twice that distance away from the Gulf, up the Shatt al Arab, and even in the best of times it has a three-month cargo bottleneck. Umm Qasr, the Iraqi naval base, lies on the border with Kuwait, and can only be reached by sea through a narrow passage between the Iraqi shore and Kuwaiti islands. The approach to Fao and the entrance to the Shatt estuary is commanded by Iranian artillery and naval posts on and around Abadan island.