Kōchi's Sunday market — Nichiyō-ichi — has been running for around 300 years and is one of the great open-air markets in Japan. It stretches for about a kilometre along Otesuji-dori, the city's main boulevard, with hundreds of stalls selling fresh vegetables and fruit, flowers and plants, antiques, secondhand tools, ceramics, and ready-to-eat food. The vendors are mostly farmers and local producers, not tourist traders.
It runs every Sunday from around 8am to 5pm, with early morning being the best time to beat the crowds. Try the local yuzu products (the region grows some of Japan's finest yuzu citrus) and the grilled katsuo skewers. The market is free to wander; food and purchases are priced in Japanese yen, cash preferred.