"Besides that, there are plenty of other benefits, but I won't go through them all now. Instead, I'll tell you how to achieve Constant Concentration..."
Tetsu no Sosuke recalled his time at the Butterfly Estate and couldn't help smiling. He spotted Shinobu Kocho, who had come over at some point, and said, "Once we're done here, I don't know if you'll have time, but if you do, I recommend visiting the Butterfly Estate. My sister-in-law made some interesting gourds you can use to train your Breathing Techniques and increase your lung capacity. With greater lung capacity, your Breathing Techniques might become a little easier, and the gourds give you a way to measure your progress. The training works both ways: as you keep blowing into the gourds and bursting them, you practice your Breathing Techniques, and when you can burst one, it proves you may be ready for Constant Concentration. As for tricks, there really aren't any. You just train day after day. Whether you're eating, walking, using the bathroom, or sleeping... you must maintain your Breathing Technique at all times. That will strengthen your body, hone your Swordsmanship, and temper your mind. Eventually, you'll master it."
Tanjiro listened closely. Even Zenitsu Agatsuma paid serious attention for once.
Shinobu Kocho pursed her lips. "The gourds were your idea. Why are you giving me the credit?"
After leading the two younger ones and one older one through their morning training, Tetsu no Sosuke and the others went back for breakfast.
Yushiro was an excellent cook. Tetsu no Sosuke had no idea how he did it.
Despite being a demon, Yushiro acted just like a professional maid... Well, a butler.
Tanjiro and Zenitsu Agatsuma ate their fill. Tetsu no Sosuke felt he shouldn't gorge himself as they did, so he ate only