An OVA bundled with the special edition of the fifth manga volume.

Seki-kun starts shining his desk during class. Amazed at the effect of his work, Yokoi-san finds herself being dragged into his want to shine more desks.

Whilst participating in a disaster drill, Rumi notices that a robot family that Seki has brought into class is taking the drill more seriously than Seki himself, prompting her to take responsibility for them.

Seki creates an elaborate post office system for passing notes around the class; with many protocols that prevent Rumi from giving him a note of her own.

Seki crafts another shogi tale, this time depicting a princess who marries a pawn but is soon kidnapped.

As the class watches an instructional video, Seki plays a game of "Shogi vs. Chess" in the dark, with Rumi eager to help the shogi pieces as they struggle against the black chess pieces hidden in the darkness.

Seki puts on a blindfold and plays a game of fukuwarai, which soon evolves into a twisting story about family life.

Rumi learns of a surprise belongings inspection, believing it to be the perfect chance for Seki to get busted. However, she becomes concerned about the robot family, especially when Seki seems to make no attempts to hide them properly.