English Art/Literary Art, Arts & Crafts, Painting literature

The term " for the piece" comes from the sentece like this:" When she walked out of the store, she saw the Japanese woman coming toward her, the white-haired woman, and she wore a padded jacket and had her hands concealed. Her hands were fisted up inside the sleeves of her jacket , for warmth, and she watched the woman, sleeves seemingly empty, and cursed herself for not having thought of this for the piece, because it was fantastic, no hands, it was everything she needed to know about the woman and would have been perfect for the piece..."

I wonder how to understand " for the piece" here?