Blizzard v0.8

A native engine that thinks on several cores. On two cores Blizzard 0.8 scored +43 =53 −4 against 0.7
(69.5%, +143 Elo, 95% interval +100 to +191) in 100 games at 0.2 s per move. Against Stockfish 19 at its
highest limited setting (3190) it scored +11 =14 −5 (60%).

What's new

Native programs for Windows and Linux. The downloadable engine is no longer JavaScript running in Node.js:
the C core is compiled straight to machine code, with AVX2 instructions for the network. On one core it is about
20% faster than the WebAssembly build, and the Windows download shrank from 34 MB to 2.9 MB (with both programs).
blizzard-old-cpu.exe is the same engine for processors without AVX2.

Several cores at once. The new Threads option runs the search on several cores (Lazy SMP: every thread
searches the same position and they share one transposition table). By default Blizzard takes half of the
cores, up to 8. On two cores it searches about 2.7 million positions per second instead of 1.4 million.

Evaluations on Stockfish's scale. On 1,411 positions compared with a deep Stockfish 16 analysis (a million
nodes each), Blizzard's evaluations pointed to the same side in 99% of positions, but its numbers ran
about 8% larger on a typical position. Shown evaluations are now scaled to match, in the UCI engine, in the
browser and in game review.

Website. The logo now slowly turns on the home page.

Strength

Match	Games	Score	Elo difference (95% interval)
0.8 on 2 cores vs 0.7	100	69.5%	+143 (+100 to +191)
0.8 on 1 core vs 0.7	29	63.8%	+98 (+22 to +185)
0.8 on 2 cores vs Stockfish 2800	30	93% (0.7 scored 81%)	+458 (+334 to +798)
0.8 on 2 cores vs Stockfish 3190	30	60% (0.7 scored 50%)	+70 (−18 to +169)

Every match: 0.2 s per move. Stockfish 19 is the single-threaded browser build, limited with UCI_Elo;
Blizzard 0.8 played it on 2 cores. More cores make Blizzard stronger still, but this was measured on a
two-core machine only. Full-strength Stockfish, without a limit, is still far stronger. These are not
FIDE or CCRL ratings; they compare Blizzard versions under the same conditions.

Downloads

File	For	SHA-256
blizzard-0.8-windows.zip	Windows 10/11, 64-bit, nothing to install	2c3263e0e0d0fd72d299b5eaa96fd74c9ee4bc6da6fc70d6ab31706fbcb1c877
blizzard-0.8-universal.zip	Linux (ready program); macOS and others with Node.js 18+	be31ac8ddbc7b69318654445a5f6a1c4fb2a2cb809eb590ea9f0ebeeb6b1fe7a

Unpack, then add blizzard.exe (or blizzard-linux, or node blizzard-uci.js) to Arena, Cute Chess,
En Croissant or any other UCI program. Play it in the browser at
sacon1s.github.io/blizzard.

Upgrading from 0.7

• Replace the old files. New options: Threads, Move Overhead, Clear Hash; Hash now defaults to 64 MB.
• UseNNUE (the old hand-written evaluation) is only in the Node.js version, blizzard-uci.js.
• The programs are not code-signed: if SmartScreen warns, click More info, then Run anyway.