You are playing Black.

Why should Black recognize White’s reference first cube situations?

White to play. To recall, a reference first cube in a cash game has the equity of Double and Take equal to the equity of wait to double. High-quality bot evaluations (long rollouts come later) suggest this position is almost a reference first cube for White. Whether rollouts confirm it as fact is not relevant to Black, only important to White. How so? To improve her overall skill, White must refine her cube actions, but Black has no actions to refine in this situation.

Still, Black should detect and note that White is near a reference first cube. Why? Undoubled, White’s next checker play followed by Black’s next checker play will inform both White and Black of an imminent cube action. White does not want to miss a pending cube opportunity. Black does not want to blunder by taking a cube that is a clear drop. By comparing how the ply improves the position when first White played then Black played, an annotated history of the ply can help confirm the Take or Pass for Black.

In this game, White waits to double. Then White rolls 55s, and turns her runners into an escaped Houdini position of 11pt and midpoint, plus betters her pip count lead to almost three rolls. Very good.

Black needs to muster a concerted response. Black rolls 11s, a good roll for making an anchor thereby reducing gammon exposure, but a roll too slow to combat White’s running game plan. Black has an average holding game. Further, Black exposes an outfield blot to a pair of directs, twenty shots. Worth noting, although the outfield blot is likely to be hit, White can selectively hit this blot to help clear her 13pt and 11pt. White is not committed to killing the blot.

This “She-said, He-said” ply suggests Black must pass the imminent cube. Since the equity change is hinged on a near reference first cube, a history of the ply is pinned to the start of the doubling window, thus providing extra context for Black. To improve his skill, Black must refine his cube actions of Take or Pass, using the prior reference cube situation. However, White has only one action in this situation: Double.

Using White’s reference cube situation as a guide, Black knows his correct cube action is Double/Pass.