The Opening Almanac VOL. I

Bad chess. Good results. Compiled from several billion regrettable decisions.

CHASE UPSIDEAVOID DANGER
BalancedPrices dangerous replies without vetoing creative lines.

Sicilian Defense

Open · Modern variation

M
Population · Mortals2.4B games sampled
WHITE TO MOVE
THE SCAM, EXPLAINED

Prep for the humans. Not the chess gods.

The engine already knows how to defend. Your opponent is called rookEnjoyer94.

01 · THEIR BLUNDERS ARE DATA

“Best defense” is a bedtime story.

Masters, Mortals, and Noobs make different mistakes. We weight every reply by what that rating pool actually plays—not by what an engine demands.

02 · YOUR BLUNDERS GET PATCHED

We replace the crowd with your prep.

On your turns, the Almanac commits to one learned move. On theirs, it keeps the messy human reply distribution. One burgundy arrow is your move; several arrows are their habits.

03 · THE NUMBER IS THE POINT

How often do you bank points?

Expected Score asks what happens if you know our theory and they keep being human. It is not “+0.2 after perfect play.”

Marginalia № 2 How the Almanac chooses a move For the sickos who see Σ and lean closer.

We replay the position against what your chosen population actually does next, then score the resulting wins, draws, and losses. On your turn we recommend; on theirs we forecast.

+1 win0 draw−1 loss
01 · THE AVERAGE

What usually happens

𝔼[U] = P(win) − P(loss)

Every result comes from real games in the selected rating pool. A draw is zero; a win and a loss pull equally in opposite directions.

02 · THE BAD END

What if they find it?

CEc(U) = −log 𝔼[e−cU] / c

When building a finite repertoire, dangerous branches become progressively more expensive as Cowardice rises. Nothing is hard-banned; one unlikely refutation simply has to earn its risk.

03 · YOUR TASTE

What “Cowardice” buys

bad branch weight ∝ p · e−cU

At Fearless we chase the best average. Toward Fortress, replies that leave you in trouble matter more and more—even when they are not the population’s favorite.

YOUR MOVEplay arg maxa RiskAdjustedValue(s, a)Choose the best result at your Cowardice setting.
THEIR MOVEexpect Σa ppool(a ∣ s) · V(sa)Weight replies by what this pool actually plays.

Not engine truth: this ranks moves for the humans you selected. Stockfish has infinite patience; your opponent has three minutes and a pulse.

Drop a position

Paste a FEN. We’ll find the human move from here—not the move that survives forty plies of engine therapy.

COMMON STARTING POINTS