In the background to the right, next to a lancet window framing a landscape, a lady, dressed in black, was reading the book that lay in her lap. Completing the scene were the painstaking details typical of the Flemish school, recorded with a perfection that bordered on the obsessive: the furniture and decorations, the black-and-white tiled floor, the design on the carpet, a tiny crack in the wall, the shadow cast by a minuscule nail in one of the ceiling beams. The painting of the chessboard and chess pieces was executed with the same precision as the faces, hands and clothes of the people depicted, with a realism that contributed to the painting’s extraordinarily fine finish, its colours still brilliant despite the inevitable darkening caused by the gradual oxidation of the original varnish.

Who killed the knight? Julia looked at the photo she was holding and then at the picture, where, to the naked eye, not a trace of the hidden inscription was visible. Even closer examination, using a binocular microscope x7, revealed nothing. She lowered the blind over the large skylight, plunging the room into darkness, and near the easel placed a tripod on which was mounted an ultraviolet lamp. Under its rays all the oldest materials, paints and varnishes would show up as fluorescent, whereas more recent ones would appear dark or black, thus revealing any later repainting and retouching. In this case, however, the ultraviolet light revealed only a uniformly fluorescent surface, including the part concealing the inscription. This indicated that it had been painted over either by the artist himself or very soon after the painting was completed.

She switched off the lamp and raised the blind. The steely light of the autumn morning again spilled onto the easel and the painting; it filled the whole book-cluttered studio, its shelves overflowing with paints and brushes, varnishes and solvents, the floor a jumble of carpentry tools, picture frames and precision instruments, antique sculptures, bronzes and wooden stretchers, pictures that rested, face to the wall, on the valuable but paint-stained Persian carpet.