The southern and western parts of the peninsula have well-developed plains, while the eastern and northern parts are mountainous which is hard for farming. Because the mountainous region is mostly on the eastern part of the peninsula, the main rivers tend to flow westwards. Two exceptions are the southward-flowing Nakdong River and Seomjin River. Thus, the northern and eastern land are more dry and are not suitable for rice growing which is main food for Korean. However, the northern part of the Korean Peninsula has the most abundance of natural resources, including coal, gold, and magnesite. Important rivers running westward include the Amnok River, the Chongchon River, the Taedong River, the Han River, the Geum River, and the Yeongsan River. These rivers have vast flood plains and provide an ideal environment for wet-rice cultivation. Thus, the southern and western parts provides most food for the whole country.(https://en.wikipedia.org/wiki/Korea#Geography)