The bamboo bow was a museum piece, but the black alloy quiver that protruded above [Hideo's] left shoulder had the look of the best Chiba weapon shops. (22.21)
Hideo's weapon displays to us his stance on violence. On the one hand, the bamboo bow shows that he has an old-fashioned code of honor. However, the black alloy quiver means he's updated his code to be useful in the future society.