Ever since volume 2 I've been impresed by how brave Aadachi is. A bit crazy in excecution but for someone who spent their whole life devoid of human connections, as soon as she realise what Shimamura does for her mentally, she seeks out that one thing she needs in her life with all her might. That's what makes the last few lines in ending of vol8 so good when she basks in the fruits of her own determination.

Tarumi is the opposite, her bond was natural and she clearly enjoyed it a lot, but she let it slip and didn't have the courage to reclaim it. When another chance arise she did her best to regain her place but never took the extra steps to claim what she really want. I feel like that's how most childhood relationship troupe in the Japanese media falls apart.

Coming out to a close friend, in japanese society no less, must be very tough, I'm not gay so I have no idea how to even process that kind of feeling. Tarumi clearly wasn't sure how Shimamura would react to that kind of affection and didn't want to make that leap.

But in comparison Adachi wasn't even that bothered with Shimamura's preference, as soon as she realise she wanted something more she went straight for it, 3 times, even if she thumbled the first two, and Shimamura saw through all that once she realise what Adachi habours, "Adachi would rather die" really sums it all up, the straightforwardness that is the complete opposite to herself is what got her hooked.
I guess that's how Adachi won the Shimabowl. She's truly my one of my favourite characters in this genre.