in June 1862, and sent a small expeditionary force to Pahang to support Tun Koris when war broke out in August 1862. During the first two years of his reign, Abu Bakar expanded the kangchu system pioneered by Daeng Ibrahim. He issued Western-style contracts (termed as Surat Sungai in Malay, literally "River Documents") to the Kapitan Cina (Chinese leaders) who had established riverside plantations along in Johor. Letters of authority (Surat Kuasa) were issued when the first Chinese leaders began settling in Johor during the 1850s. Abu Bakar quickly established goodwill relations with the Kapitan Cina; a Malay administrator who could speak the Teochew dialect (the language spoken by most Kapitan Cina) and read Chinese was employed for these purposes. He also employed the service of a Chinese contractor from Toisan, Wong Ah Fook, to oversee the construction of Istana Besar. Various Chinese dialect groups began to compete for commercial interests in the 1850s and 1860s. This led to communal violence. Abu Bakar and the Kapitan Cina in Johor (who were mainly migrants from Chaozhou) tried to assimilate Chinese entrepreneurs of non-Teochew origin. Abu Bakar gave official recognition and support for the Johor branch of the Ngee Ann Kongsi, which was seen as a secret society in Singapore at that time. As Johor prospered from the large revenues generated from the gambier and pepper plantations managed by the Kapitan Cina, Abu Bakar gave generous provisions to the Kapitan Cina in recognition for their contributions to the state; among his beneficiaries was a long-time family friend, Tan Hiok Nee, who was given a seat in the state council. The plantations operated relatively independently of the state government, and Abu Bakar was worried by the possible danger to the plantations in the event of an economic crisis. Shortly after a financial crisis broke out in Singapore in 1864, Abu Bakar imposed new regulations on these plantations, as many of them were owned by Chinese businessmen from Singapore. The Kapitan Cina and the Singapore Chamber of Commerce were particularly disturbed by the new regulations, and accused Abu Bakar of attempting to impose a trade monopoly over Johor. The British government pressured Abu Bakar to retract the regulations, which he did in January 1866. In addition, the Kapitan Cina also faced considerable difficulties in securing new agreements with Abu Bakar. The crisis was only resolved in 1866 after Abu Bakar designated five new ports