bsp;×&nbsp;256. A sequence element is appended, encoding whether it is white or black to move, since the primary model does not care, but the commentary model very much does. Then, a <em>positional encoding</em> like that used in the transformer paper is applied to the final 129&nbsp;×&nbsp;256 sequence, so that the attention mechanism of the transformer knows which position was before and which was after. Although it seems like attention alone would know about position, really it just knows about content