Asukaike Pond sat in a valley in the hills of Asuka, at the southern end of the Nara Basin. Nobody suspected what lay beneath it. When the pond was drained in 1991, the archaeological potential was immediately obvious, and systematic excavations began in 1997. What emerged was staggering in scale: the ruins extended 230 meters from north to south along the valley, with a clear division between a southern workshop zone and a northern administrative zone separated by a wall running across the middle. The southern workshops were not a jumble of activity but a carefully planned industrial district, each craft allocated its own space. Metal processing covered gold, silver, copper, and iron. Bead-making handled glass, crystal, and amber. Other areas specialized in lacquerware, tiles, and tortoiseshell. The level of organization suggested centralized management, not independent artisans working side by side.

The most significant discovery was numismatic. Among the workshop debris, archaeologists found 560 unfinished Fuhonsen coins along with the casting molds and poles used to produce them. Before this find, the Wadokaichin -- minted in 708 AD -- was widely considered Japan's oldest coin. The Fuhonsen pushed that date back by at least a decade, possibly more. Wooden tablets excavated from the site confirmed that operations dated to the reigns of Emperor Tenmu and Empress Jito in the late 7th century, extending into the 8th century. Another 33 completed Fuhonsen coins turned up in the northern administrative zone. The coins were made of copper and antimony, and their presence alongside the production equipment left no room for doubt: this was a mint, and it was operating before the date previously accepted for the birth of Japanese coinage.

The northern zone told a different story from the furnaces to the south. Here, archaeologists found a stone-paved well, a square stone pond, water channels, and a building constructed in the formal style of a government office. Large numbers of wooden tablets -- the bureaucratic records of 7th-century Japan -- confirmed that this area served an administrative function, likely managing the workshops below. The site sits just southeast of Asuka-dera, one of Japan's oldest Buddhist temples, and northeast of Asuka Kiyomihara Palace, the imperial residence. This proximity has generated two competing theories about who controlled the workshops: one holds that they were attached to Asuka-dera, serving the temple's needs; the other argues they were a state enterprise linked to the imperial household, possibly an early version of the Takumi-ryo, the Ministry of Crafts that would later be formalized under the Ritsuryo legal system of the Nara period.

What the Asuka Pond Workshop Site reveals is the material sophistication of late 7th-century Japan. This was not a subsistence economy cobbling things together. Over 300 furnaces burning simultaneously required fuel supply chains, raw material procurement across multiple trades, and a workforce organized by specialty. The artisans working here produced the physical trappings of imperial power: coins for commerce, gold ornaments for the court, glass beads for decoration, lacquerware for ceremony. The site was designated a National Historic Site of Japan in 2001, recognizing both its archaeological significance and its role in reshaping understanding of early Japanese statecraft. Today the valley where the pond once stood is quiet, the furnaces reduced to foundations and ash layers. But the scale of what operated here -- a centralized, multi-industry production facility serving the needs of an emerging nation-state -- remains remarkable.