All the hashira decide to train together, and to get them really motivated, Ubuyashiki tells them that each day, the Pillar who "wins" the training session gets to spend time with Tanjirou all by themselves.
The hashira training is a success, but also wild and chaotic because they all go feral on each other trying to win.
They get a lot better at fighting quickly; they adapt and improve because they desperately want to win at least once so they can go on a date with Tanjirou. They know Tanjirou doesn't think of them as dates, but the hashira happily imagine that's the case.
It's not easy to win; the one who ends up spending the most time with Tanjirou is Gyomei, to no one's surprise; he's the strongest for a reason.
But after a lot of effort, each one wins at least once; Kyojuro and Sanemi win twice, and the wind hashira makes ohagi for Tanjirou on one of his "dates" with the redhead.
Aoi watches everything with irritation, but she's secretly glad to see them all so happy. They deserve it.
Tanjirou clearly enjoys spending time with every single one, although sometimes he wonders why it has to be one at a time.
Ubuyashiki and his family have a bit of fun; it's a great idea to use that as a motivator for the Pillars, but it's also a great way to encourage them to confess.
Most people think that Tanjirou's oblivious nature is the main reason why the Pillars are not properly dating him already, but it's also the fact that they prefer to wait for more peaceful times so they can actually confess.
But in Ubuyashiki's experience, sometimes peaceful times arrive too late, and not everyone stays to experience them.
Of course, he wants them all to survive and live happily after they defeat Muzan, but he's not sure they can achieve all of that.
Which is why he's trying different methods to encourage them to be honest with Tanjirou so they all can begin to enjoy their time with him.
It'd be really nice to have a wedding in the hashira headquarters, especially if the nine Pillars are the ones who are getting married.
However, even though they haven't told Tanjirou the whole truth, Ubuyashiki can tell all of them enjoy every second they get to spend with him.