@Zerael it only really works when they are also "first girl" but if they aren't then 99% of the time they lose
in fact when a character has both First girl + childhood friend they have 100% chance of winning. I have not seen someone with this two traits combined lose.
I just wish it won't go too much into harem theme becoming another average harem rom-com and will just focus on Hanako as she is best point of this manga.
Oh no, the childhood friend who never asserted herself has arrived.
If she had approached him on the first day of school, he would have clung to her side like a lost puppy and he never would have met big tiddy yankee Hana Onee-san.