Curiously—or perhaps not—Riotori have excellent memories for names and people. Their sense of smell, and the individual fragrance differences of the females (or the scent of the males) is the primary reason. So as the two met and admired several females, they had not need to keep any kind of written notes. Their memories were perfect for this undertaking.
When they came together many hours later, both had identified four young women they felt were above the rest in the categories of physical attractiveness, practicality, kindness, a willingness to not talk too much, and—extremely important—reasonable and polite families.
There developed one small issue. Fortunately, the two had anticipated the possibility and had, during their trip, come to an agreement about how the difficulty would be resolved.
One of the four on each list was the same female.
They would not compete against each other for her affections.
In accordance with their agreement, neither asked or declared when during the day he or his twin had made her acquaintance. There would be no "I saw her first!" argument.
The odds were that she was ranked differently on the two lists.
She beat the odds. She was the first choice on both lists. The twins glared at each other, then laughed. This possibility, too, had been discussed. Both would set their first choice to the side and pursue their attractions to the other three.
Fortunately, only the one young female had managed to attract both young men.
There was only question, and each twin thought it but kept his concern to himself: would his brother keep his word?