Light Yagami's strategic planning throughout the series is significant as it showcases his intelligence, cunning nature, and ability to outmaneuver his opponents. His meticulous planning, calculated risks, and manipulation of situations are key elements that drive the plot forward and highlight his character development as a complex and morally ambiguous protagonist. Additionally, his strategic planning also serves to engage viewers by creating suspenseful and unpredictable situations that keep them invested in the story.
