I've been thinking about this book more than I probably should, and there's something deeper going on beneath the farming and shopping surface.
The space itself — it started small and keeps growing. "When crops mature, the space would expand." This isn't just a convenient plot device. It's a metaphor for self-sufficiency, for building something from nothing. Every crop she plants, every seed she saves, every expansion of that space represents her taking control of her own life. She's not dependent on anyone. The mountains, the dogs, the space — it's her entire world and she's building it brick by brick.
Then there's the disguise. She dresses as a servant, puts soot on her face to hide her beauty. "From a distance, it looked like a large dark birthmark." Why does she do this? Because the world outside her mountain isn't safe for someone like her. The disguise is both protection and commentary — she has to erase herself to survive in society. But inside the space, she doesn't need to hide. She can just be Gu Shiyi.
And the bamboo rats — caught by dogs, sold for silver, used to buy seeds and supplies. It's this beautiful cycle of giving and receiving. The dogs hunt, she sells, she invests back into the future. There's a theme here about interdependence and smart resource management that I think a lot of readers glide right past.
The salt detail hit me too. "In the deep mountains, even without grain, she wouldn't starve... But salt was different." Salt as a symbol of civilization, of connection to the outside world, of the thin line between survival and thriving. She could survive alone in the mountains, but salt pulls her back to town, back to society, back to the cycle of trade and exchange.