The reason is considered that by the 17th century sets of 'inro' and 'netsuke' had spread not only among higher-ranking samurai and court nobles but also among people involved in tea ceremony culture, as well as merchants and townspeople, as an expression of style.
その要因として、17世紀頃までに「印籠」・「根付」のセット普及が、高級武士・公家から茶道・商人・町人までに及び、その粋なファッション表現が昇華されたから、と考えられる。