Later, during its golden era, in the 17th century, its and political influence expanded as far as Satun in southern Thailand, Johor in Malay Peninsula, and Siak in what is today the province of Riau. As was the case with most non-Javan pre-colonial states, Acehnese power expanded outward by sea rather than inland. As it expanded down the Sumatran coast, its main competitors were Johor and Portuguese Malacca on the other side of the Straits of Malacca. It was this seaborne trade focus that saw Aceh rely on rice imports from north Java rather than develop self sufficiency in rice production.