He didn't tell anyone what day it would be.
Not Saki, who would have wanted to help with logistics. Not Yoru, who would have wanted to discuss it with the thoroughness of someone planning her own eventual proposal vicariously. He simply decided, on a Wednesday morning, that it would happen that evening, and spent the day moving through his usual routine with the ring sitting in his jacket pocket like something both impossibly heavy and entirely natural to carry.
The ring itself had taken longer to choose than he'd expected. Not because of the cost — that had never been the difficulty — but because he'd wanted something that meant what he needed it to mean, and meaning didn't come from carats or settings. He'd gone, eventually, with something simple. A thin band, a small stone, nothing that would draw attention to itself the way Nana never drew attention to herself even while holding an entire household together.
