Chapter 16

After a television spot for a scarce sugar-brand backpack airs, Hana tells Aoi she wants one for the start of school. Aoi warns that the item is limited and likely near impossible to track down. Overhearing them, Sakamoto quietly phones a contact and heads to a department store with Shin, privately framing the outing not as shopping but as a critical operation to secure the bag. As Shin muses about Hana growing up and boys someday chasing her, Sakamoto's imagination turns violent, and Shin reminds him it is only a daydream.

A store announcer reveals just twenty of the coveted backpacks are available, and the mob of parents erupts, shoving one another aside. Warned that families across the country treat owning one as the ultimate parenting badge, Sakamoto and Shin brace themselves. Shin gets yanked and elbowed by a fierce grandmother, and the flood of desperate thoughts he reads from the crowd leaves him dizzy enough to retreat. Sakamoto insists no one is more determined than a father fighting for his kid.

Down to the final bag, Sakamoto grabs it, only to be choked and pummeled by the women around him, flashing back to assassin training where he once fended off sharks at great depth. He breaks free, hands the prize to Shin, and staggers to pay, but the terrified cashier flings the bloodstained bag away. In the scramble, Sakamoto recalls Hana's birth, her first smile blooming like a flower, and how that image gave her the name. Moved, Shin realizes how deeply Sakamoto treasures her. Sakamoto ultimately leaps from an upper floor to snatch the bag and stands triumphant, and Shin hails him as a legendary father.

Sakamoto mobilizes to obtain a hard-to-find limited edition backpack for Hana, dragging Shin into a brutal department store crush. He survives a coordinated beating from rival shoppers and, bloodied, secures the last bag by diving from a higher floor. A flashback unpacks the emotional roots of Hana's name, tied to her newborn smile. Hana later attends her school orientation, and a boy immediately offers her a flower, leaving Sakamoto quietly seething back at the shop.

Titled Department Store War, this is the sixteenth chapter of Sakamoto Days and belongs to the Lab Arc. It appeared in the sixteenth 2021 issue on March 22, 2021, and runs nineteen pages within Volume 2. The cover features Sakamoto alongside Aoi and Hana. The comedic entry centers the family and introduces the aggressive shoppers Kazuko and Sachiko, with Lu Shaotang closing on Sakamoto's lingering irritation.