As sign that winter is on the way, roasted chestnut stands have sprung up all over the city. They do the roasting on the spot, and there are usually long queues of customers.
The last time I bought some, they were 8 yuan per 500g (just over 1 USD). This stand gives out a free 'chestnut peeling machine' (剥栗器) when you buy 500g. I should have asked to look at it. We were given a small plastic thing with a serrated edge with our chestnuts a few weeks ago, so it's probably one of those. There are better offers at other stands around town: some places are doing 1kg for the price of 500g.