bars are offered, or a gold exchange standard whenever other gold-convertible currencies are offered. John Maynard Keynes referred to both standards above as simply the gold exchange standard in his 1913 book Indian Currency and Finance. He described this as the predominant form of the international gold standard before the First World War, that a gold standard was generally impossible to implement before the 19th century due to the absence of recently developed tools (like central banking institutions, banknotes, and token currencies), and that a gold exchange standard was even superior to Britain's gold specie standard with gold in circulation. As discussed by Keynes: The classical gold standard of the late 19th century was therefore not merely a superficial switch from circulating silver to circulating gold. The bulk of silver currency was actually replaced by banknotes and token currency whose gold value was guaranteed by gold bullion and other reserve assets held inside central banks. In turn, the gold exchange standard was just one step away from modern fiat currency with banknotes issued by central banks, and whose value is secured by the bank's reserve assets, but whose exchange value is determined by the central bank's monetary policy objectives on its purchasing power in lieu of a fixed equivalence to gold. Rollout outside Europe The final chapter of the classical gold standard ending in 1914 saw the gold exchange standard extended to many Asian countries by fixing the value of local currencies to gold or to the gold standard currency of a Western colonial power. The Netherlands East Indies guilder was the first Asian currency pegged to gold in 1875 via a gold exchange standard which maintained its parity with the gold Dutch guilder. Various international monetary conferences were called up before 1890, with various countries actually pledging to maintain the limping standard of freely circulating legacy silver coins in order to prevent the further deterioration of the gold–silver ratio which reached 20 in the 1880s. After 1890 however, silver's price decline could not be prevented further and the gold–silver ratio rose sharply above 30. In 1893 the Indian rupee of 10.69 g fine silver was fixed at 16 British pence (or £1 = 15 rupees; gold-silver ratio 21.9), with legacy silver rupees remaining legal tender. In 1906 the Straits dollar of 24.26 g silver was fixed at 28 pence (or £1 = 8 dollars; ratio 28.4). Nearly similar gold