TV-Series
Description
Nakai is Nishikata and Takagi's middle school classmate, distinguished by his notable height, short brown hair, and eyes often closed due to poor vision that necessitates sitting near the classroom board. As an adult, he retains his significant height but develops a more muscular build, adding stubble and slightly longer sideburns. His personality is calm, friendly, and laid-back; he prefers time with male friends like Nishikata over solo interactions with his girlfriend, Mano, finding those challenging. Despite appearing romantically dense and sometimes frustrating Mano, who wishes he would take more initiative, he demonstrates genuine care and quiet thoughtfulness toward her and their relationship. He also supports others, particularly encouraging Nishikata in his interactions with Takagi.
His relationship with Mano is central. They date throughout middle school, though Nakai struggles with the nuances of pleasing her during their alone time. Key romantic moments include riding a waterslide together after hearing a rumor it makes couples fall in love (OVA), and in Chapter 124 of the manga, Mano becomes upset when he initially refuses to write their names in a book at the top of 415 steps—a legend promising eternal togetherness—only for him to reveal he had already written her name there previously. They happily watch fireworks at a summer festival (Season 2 finale) and share a kiss (Chapter 163). Over a decade later in the spin-off manga, Chapter 129 confirms they live together, and Chapter 265 confirms their marriage.
Nakai's friendship with Nishikata begins when the latter transfers into their middle school; Nakai approaches him after being impressed by Nishikata arriving late on the first day. They remain close, engaging in activities like visiting water parks. Nakai recognizes the romantic tension between Nishikata and Takagi and frequently encourages Nishikata to act. Nishikata, in turn, indirectly assists Nakai with Mano, such as initiating a four-person exchange diary involving Takagi and Mano.
In the live-action film, set ten years after middle school, Nakai works alongside Nishikata as a teacher at their alma mater, Momomi Middle School, and is engaged to Mano. His surname, Nakai (中井), means "middle" (中) and "well" or "mine shaft" (井). Based on the over-ten-year time skip after middle school graduation (typically age 14–15 in Japan), his estimated age in the spin-off is 26–27.
His relationship with Mano is central. They date throughout middle school, though Nakai struggles with the nuances of pleasing her during their alone time. Key romantic moments include riding a waterslide together after hearing a rumor it makes couples fall in love (OVA), and in Chapter 124 of the manga, Mano becomes upset when he initially refuses to write their names in a book at the top of 415 steps—a legend promising eternal togetherness—only for him to reveal he had already written her name there previously. They happily watch fireworks at a summer festival (Season 2 finale) and share a kiss (Chapter 163). Over a decade later in the spin-off manga, Chapter 129 confirms they live together, and Chapter 265 confirms their marriage.
Nakai's friendship with Nishikata begins when the latter transfers into their middle school; Nakai approaches him after being impressed by Nishikata arriving late on the first day. They remain close, engaging in activities like visiting water parks. Nakai recognizes the romantic tension between Nishikata and Takagi and frequently encourages Nishikata to act. Nishikata, in turn, indirectly assists Nakai with Mano, such as initiating a four-person exchange diary involving Takagi and Mano.
In the live-action film, set ten years after middle school, Nakai works alongside Nishikata as a teacher at their alma mater, Momomi Middle School, and is engaged to Mano. His surname, Nakai (中井), means "middle" (中) and "well" or "mine shaft" (井). Based on the over-ten-year time skip after middle school graduation (typically age 14–15 in Japan), his estimated age in the spin-off is 26–27.