What do the bridge and river represent in this story?

The river in the story represents two types of division in Hitoshi and Satsuki's lives. When Hitoshi is alive, it represents the fact that they live separate lives and come together when they can. When Hitoshi dies, the river represents the divide between life and death. The bridge also represents the meeting place when Hitoshi is alive, band the only place that Satsuki and Hitoshi meet after he dies.