What makes Sign by Mr. Children notable?

'Sign' achieved significant commercial success, reaching number one on the Oricon charts and becoming a staple in Japanese pop culture. Its poignant themes resonated with listeners, contributing to Mr. Children's reputation for crafting deeply emotional music that reflects societal sentiments. In 2004, Mr. Children was riding high on their commercial success following the release of their earlier album 'It's a Wonderful World' in 2003. 'Sign' marked their continued evolution as a band, showcasing a maturation in both sound and lyrical themes, solidifying their status as one of Japan's leading pop-rock acts.