What is the symbolic meaning behind the Statue of Times Forgotten in the novel, Tokyo Ueno Station?

The Statue of Times Forgotten in Ueno Park is a symbol of collective Japanese history and Kazu's regret at missing out on the lives of his children. The statue was erected to honor the dead from the firebombing during World War II and features a woman holding onto her two children. "Every time I saw the Statue of Times Forgotten, I felt like I was being forced to face those times gone by," Kazu explains, "Yoko and Kōichi were only two years apart, so there must've been a time when they looked just like this" (48). Kazu cannot remember such a time because he barely saw them throughout their childhoods.