The significance of Takemichi's relationship with his younger self in the anime "Tokyo Revengers" lies in the opportunity it provides for growth, learning, and self-discovery. Through his interactions with his younger self, Takemichi is able to reflect on his past decisions, understand his motivations, and ultimately work towards changing his future. This relationship serves as a powerful metaphor for self-reflection, personal development, and the ability to make positive changes in one's life.