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How accurate are the Japan - Pro Baseball odds?

The closing prices of 1,077 finished games since Fri 9 Aug 2024, set against what happened: the chance the market gave, with the bookmakers' margin removed, next to how often it came in. A record of what the market did, not a tip.

The market's record

1,077 games, 2 bookmakers
  • Closing favourite won 58% 622 of 1,077 games
  • Market Brier score 0.481 0 is perfect; a coin flip scores 0.500
  • Average closing payout 95.0% 100% minus the bookmakers' margin
  • Games covered 1,077 Fri 9 Aug 2024 to Fri 16 Oct 2026

923 of the 2,000 games finished in that time are left out: no bookmaker had a closing price on every outcome.

Market chance against what happened

30-40% chance: happened 32.6% of 291 selections 40-50% chance: happened 46.1% of 755 selections 50-60% chance: happened 53.8% of 775 selections 60-70% chance: happened 67.1% of 289 selections 100% 0%
Market said 0%100%
Happened
Market chancePriceSelectionsMarket saidHappenedDiff
30-40% 2.50 to 3.33 291 36.4% 32.6% -3.8 pts
40-50% 2.00 to 2.50 755 45.3% 46.1% +0.8 pts
50-60% 1.67 to 2.00 775 54.6% 53.8% -0.8 pts
60-70% 1.43 to 1.67 289 63.6% 67.1% +3.5 pts

Every priced outcome of every game is one selection. "Market said" is the bookmakers' average implied probability with the margin removed; "Happened" is how often that outcome came in. On the diagonal the market was right on average; above it, that kind of result happened more often than the prices said. Bands with fewer than 30 selections are left out.

Home, away

OutcomeMarket saidHappenedDiff
Home win 52.5% 53.9% +1.4 pts
Away win 47.5% 46.1% -1.4 pts

The market's average closing chance for each outcome over all 1,077 games against the share of games it won. "Home" is the first-named side.

Bookmaker accuracy

lower is better
BookmakerGamesBrier scorevs market averagePayout
Bet365 733 0.478 +0.005 95.9%
Unibet 1,031 0.479 -0.001 94.5%

Each bookmaker's own closing prices, margin removed, scored against the results of the games it priced; "vs market average" compares it with the bookmakers' average on the same games, so a negative figure means its prices were the closer. Bookmakers with fewer than 50 priced games are left out. Differences of a few thousandths are noise; a much higher score usually means the bookmaker's last price was captured well before the start, so it is the price in our archive being scored, not the trader.

Odds accuracy FAQ

How accurate are Japan Pro Baseball odds?
Across 1,077 finished Japan Pro Baseball games since 2024, the closing favourite won 58% of the time. The market's closing chance, with the bookmakers' margin removed, gave the home side 52.5% on average and home wins happened 53.9% of the time. The bands above show the same comparison price by price: a well-calibrated market has outcomes happening about as often as its prices say.
What is a Brier score?
The squared distance between the chances a bookmaker's prices gave and what happened, averaged over games: 0 would be perfect foresight, and on a three-way market a coin-flip price scores 0.667. The market average's closing prices score 0.481 in this league; the lowest single bookmaker is Bet365 at 0.478. Differences of a few thousandths between bookmakers are noise, not skill.
Does a well-calibrated market mean the odds cannot be beaten?
Calibration says the market is right on average, not on every game. A band where outcomes happened more often than the prices said is where the closing market under-priced that kind of result over these seasons. The bookmaker's margin, about 5.0% here, still has to be cleared: the closing line value calculator shows what a price needs to beat.

See the league's fixtures, results and the favourites' recent record on the Japan - Pro Baseball page, every game behind these figures in the Japan - Pro Baseball results and closing odds by season, or work out a price's implied chance and closing line value with the betting calculators.