Spock paused at the request to call him by his first name. It was not as though he had never called him Jim before, though typically it was not under these sorts of circumstances. Not for the first time, he thought back on the Kirk and Spock of the alternate reality, the pair he had witnessed the night he traveled to the Enterprise with Dr. McCoy. They, too, had been on a first-name basis, and it was not difficult to imagine that it carried over into their off hours as well.

But what he had seen that night was not relevant to here and now. Spock did not wish to imitate the lives of two individuals whose circumstances were completely different from their own. But when Kirk asked that he not use ranks for the duration of the shift, Spock didn't have any objections, and so, logically, there was no reason not to comply.

"Very well," he quietly answered. Though he did not return the captain's smile, if one looked closely they might have noticed the corner of his mouth was somewhat upturned. "Jim."

Hearing that he had experience in chess was interesting, though Spock was not yet sure how he would compare to his own ability. There was no doubt the captain was gifted in certain fields. When checking through his records back at the academy, he'd learned that, as a cadet, he'd been at the top of his class in both survival strategies and tactical analysis. And while he'd apparently served as treasurer for the xenolinguistics club, there was no mention of him being involved in chess-related extracurricular activities.

Regardless, Jim appeared quite confident in his own playing, which made Spock curious to see how their game would unfold. He considered the board for a moment before he reached for a pawn and made his first move.

While he was not opposed to conversing while they played, Spock hadn't expected a question about McCoy. He glanced up with Kirk with a faintly raised eyebrow. "I was not aware I was in need of a medical examination. Why does he wish to perform one?"