At the time when the Chinese made their great invasion into South-eastern Asia (214 B.C.) they still were employing a bronze currency under the form of knives, which were 135 millimetres (5⅖ in.) in length, bearing on the blade the character _minh_, and furnished with a ring at the end of the handle for stringing them. Under the ninth dynasty (479-501 A.D.) they used knives of the same form and metal, but 180 millim. (7⅕ in.) in length, furnished with a large ring at the end of the handle and inscribed with the characters _Tsy Kú-u Hoa_. Next the form of the knife was modified, the handle disappeared, and the ring was attached directly to the blade, but now as weight was regarded of importance, its thickness was increased to preserve the full amount of metal, and the ring became a flat round plate pierced with a hole for the string[211]. Later on these knives became really a conventional currency, and for convenience the blade was got rid of, and all that was now left of the original knife was the ring in the shape of a round plate pierced with a square hole. This is a brief history of the _sapec_ (more commonly known to us as _cash_) the only native coin of China, and which is found everywhere from Malaysia to Japan[212]. [Illustration: FIG. 21. CHINESE KNIFE MONEY (showing the evolution of the modern Chinese coins).] Except where foreign coins such as American silver dollars are employed, all payments in silver and gold are made by weight, the only money being the copper _cash_. The Chinese metric system, like our own, is based on natural seeds or grains of plants. Thus ten of a kind of seed called _fên_ (the Candarin) probably placed sideways make 1 _ts’un_ (the Chinese inch[213]), just as our forefathers based the English inch on 3 barleycorns placed lengthwise. So with their monetary system, 10 _li_[214] (copper cash) = 1 _fên_ (_Candarin_) of silver. 10 _fên_ = 1 _chi’en_ (_mace_). 10 _chi’en_ = 1 _liung_ (or _tael_ or Chinese ounce).