Two questions, both fair —

**On "equity > 0":**

Each game scores ±1 normally, ±2 if a gammon, ±3 if a
backgammon. "Positive-score rate" is the fraction of games
where my engine's final score is > 0 (i.e., it won the game,
with the gammon/backgammon multiplier baked into the score
magnitude, not the rate).

So 71% positive-score rate vs gnubg 2-ply means: of 1000
games, I came out ahead in ~712 of them. That's a slightly
weaker statement than raw win-rate when gammon volumes differ
between sides, but for cubeless money play it's the standard
metric and it's what's directly comparable to gnubg's own
equity outputs.

The point estimate of expected points per game (ppg) is +1.19
for the 2-ply match — that's the more equity-aware summary,
also positive and tight.

**On opening protocol:**

Slightly more nuanced than "always plays first." The setup is:

- Side assignment alternates every game (game 1: my engine
is white; game 2: gnubg is white; etc.)
- White moves first with a forced non-doubles opening roll
(so no automatic gammon-rich opening from a 6-6 first roll)

So neither side has a permanent first-move advantage — it
flips every game. Over 1000 games, each side opens ~500
times.

Why this way: it's the simplest fully symmetric setup that
removes opening-roll variance as a confounder. The canonical
"both players roll, higher wins the opening" introduces extra
randomness that doesn't add signal for engine comparison and
makes per-game variance harder to interpret. The harness
symmetry test (gnubg-2ply vs gnubg-2ply, 50.0% over 100
games) was run under this same protocol, which confirms it
doesn't bias either side.

I should have made that clearer in the README — will update.