Picochess v4.2.3 is out for testing

[Johan Sjöblom]

Picochess v4.2.3 is out for for the brave testers :-)

Maybe most noticable change is the new Berlin chess set on the web client, courtesy DJ Dekker. This version will also use Randy's latest engine resource files on clean installs. In addition to having the latest Stockfish in the engine resource files this version also has the Stockfish 18 in the web client.

we have fixed some bugs, two of them could have side effects as they were not trivial:

- there is a fix for the time drift on the web clock

- there is a fix for engine analysis crashing when you play really fast

Both these could cause some problems. That's why we have brave testers, right :-)

Let me know if you find problems and I will make hotfixes.

-- Johan

Complete change list from 4.2.2:
2c28982b Version 4.2.3
9cf16ad6 hotfix: preempt analysis before first info
e22ea220 hotfix: recover engine after dirty analysis stop
777c8c9b hotfix: await cancelled analysis task cleanup
3421193f hotfix: await tutor engine stops
181bc4f8 hotfix: bound continuous analysis teardown wait
7feff972 hotfix: make continuous stop guard age-based
da13a73c Await engine idle before configure()
2f658d4c Stop analysis engine safely
72eb1370 Carry fractional web clock drift
f97b58fc Fix for time drift
50535bd7 Revert "Berlin pieces"
23ba7792 Berlin pieces
011cac84 Add 'Berlin' piece set
6ad22460 Small fixes for chess variants
c2359f55 update x86_64 lite engine resource to v4.2.2
9f5a9792 hotfix: fix startup ok timing and ordering
5715887b hotfix: do not start user turn engine analysis before the game board has been updated as a result of user performing the move on the eboard
5e675663 Show tutor feedback before MAME auto-takeback prompt
aa8743d8 Clarify analyse routing comments for turn and output
b5356392 Remove obsolete always-run tutor constructor arg
ff87cb37 Retire coach-analyser as compatibility no-op
4f61c6d1 Skip engine analyser on untouched starting position
d199c9ca Update install-engines.sh
65a31cdf Keep IP text visible by avoiding immediate exit redraw
a855b1d3 Hold no-eboard spinner while showing IP in menu
12b3ccd1 hotfix(install): remove automatic Bluetooth diagnostics from installer, its not really needed
ef4b074e hotfix(install): make backup ownership chown recursive before rsync to avoid hanging.
6b59103d Security fixes
f7e1b9b4 Bugfixes
2d4cfedd Remove accidental tracked pycache artifacts
bd755c05 ajustes visuales menores
cfa179ce stockfish 18 .js  para webserver
2d936a15 Add PCS button and shorten COLOR label to CLR
9f684c6a git commit -am "Remove darkwood from selectable web board themes".  Fixes Two board theme bugs Fixes JohanSjoblom/picochess#287
9ebcbe63 Make ASCII
fc0a8930 Add game modes
f8bb9d87 Added ToC, startup sequence
c2c4ab09 Add specials FENs, alt move, game end
1bf3ac32 Technical explanation of move cycle
2febaa59 Rename board to web-board-theme and remove board-setting ambiguity (board was already taken)
c0462545 Extra chess piece sets for webserver
99369bf2 Keep these files as in master
0c4a39e7 Code optimizations
992e82f3 fix to kiosk install script - Make sure directories ~/.config and ~/.config/autostart are owned by the install user (typically pi).
77228a17 update aarch64 engine resource file for rodent3
f31fb518 Clean install should start a-stockf engine with 1 thread only. I chose Elo@2200 as the default setting.
26c505e7 update aarch64 engine resource files to v4.2.2
4980b4e3 check-git-tags: show tag target commit dates

[Luigi Vogliobene]

Thank you, Johan

[DJ Dekker]

Hi PicoChess users,

After the inclusion of the fourth set of chess pieces (‘Berlin’) in PicoChess 4.2.3, here is some background info for the sets.

Merida: The Modern Standard

Released in 1998 by Mexican designer Armando Hernandez Marroquin, Merida is arguably the most ubiquitous chess font in existence. Inspired by a book with 5000+ chess puzzles in a similar chess font, its name pays homage to the capital of the Yucatán. Merida was a pioneer in the digital transition; its later Unicode remapping ensured it became the “default” look for nearly all web-based chess platforms today.

Stylistically, Merida is defined by “warmth” and weight. Eschewing the sharp, cold lines of earlier digital efforts, Marroquin designed solid, filled silhouettes with soft curves that remain legible even at the smallest scales. The Knight is the set’s signature piece—a compact, sturdy bust with a rounded snout that strikes a perfect balance between classical gravitas and modern digital efficiency.

Leipzig: The Handbuch Heritage

Leipzig is the “high-definition” ancestor of the group, digitized by Marroquin but in its essence already found in the 1843 classic Handbuch des Schachspiels by Paul Rudolf von Bilguer (although his pawns looked rather like today’s bowling pins!). Its global reach was confirmed by its appearance in the 1897 Specimens of Printing Types by the American Type Founders Company, proving it was the professional choice for printers on both sides of the Atlantic long before the digital age.

The design is noticeably richer and more detailed than its peers, mirroring the craftsmanship of 19th-century woodblock printing. It is an “engraver’s” font: the Rooks feature individually rendered bricks and the Knight is an expressive, anatomically detailed bust inspired by classical Greek sculpture in the British Museum. Today, Leipzig remains the favorite for high-quality print publications and players who prefer a historically grounded, “old-world” aesthetic.

Alpha: The Digital Workhorse

Chess Alpha (or simply: Alpha) was created by Eric Bentzen, a Danish designer in 1998. Unlike Marroquin’s historically sourced fonts, Alpha is an original design. It was updated in 2006 by Peter Strickland (Alpha2).

Alpha’s defining characteristic is its clean, outline-based style. The pieces are drawn with clear, uncluttered contours, making the font especially suitable for output on printers and photocopiers. There is no decorative engraving or historical ornamentation; every piece is reduced to its essential recognizable silhouette. The knight is arguably Alpha’s most charming piece: a simple but graceful horse’s head that balances legibility with a hint of personality. Alpha's design has proven especially popular as a foundation for extended piece sets like the Alfaerie collection.

Berlin: The Ideological Artifact

Also the work of Eric Bentzen, the Berlin font is a digital preservation of the East German Sportverlag aesthetic. It draws on the tradition of the Berliner Schachfiguren—a distinct German lineage characterized by slender, elongated, and geometric silhouettes. For many players from the former Eastern Bloc, Berlin carries a nostalgic weight, representing the rigorous instructional manuals and state-sponsored tournaments of the Cold War era.

The most striking detail of the Berlin set is its King, which carries a visible political “scar”. In a deliberate adjustment for the officially atheist German Democratic Republic, the traditional cross—referring to the monarch’s power as derived from God—was removed and replaced with a simple ball. This makes Berlin the only one of the four classic sets included with PicoChess to bear the direct imprint of 20th-century political circumstance, turning a simple diagram into a historical-ideological artifact.

[Randy Reade]

Thanks for the work, DJ!

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[Luigi Vogliobene]

Thank you DJ

[Johan Sjöblom]

And thanks for the quite interesting background!. My chessbooks from early 1980s use Alpha, but I am pretty sure that the German chess opening books I had back then had Leipzig. Unfortunately I no longer have those so I was not able to check. Very nostalgic indeed!

[Johan Sjöblom]

More bug fixes have been merged to master now. (auto elo is still not fixed...).

Again, there are more chess pieces in the web client to chose from (courtesy DJ Dekker)... Just click the PCS button below the board to rotate the piece set. There are no new colors, but there are several to chose from. To toggle board colors click the CLR button.

One open PR is the https://github.com/JohanSjoblom/picochess/pull/315 which fixes window switching under wayland installations when you have kiosk mode chromium and a mame artwork window and you have no keyboard. Just lift any piece shortly and put it back and the window will switch. For wayland you do have to add this setting:

window-control-backend = ydotool

And on many installations you have to install ydotool manually, as its not part of the standard Raspberry packages. Its in some retro package. See also the testing instruction under the link above. For me this branch now works with wayland, kiosk and artwork.

-- Johan

[Dirk]

Thanks Johan!

I will check out the mame artwork switching….

Am 15.03.2026 um 09:39 schrieb Johan Sjöblom <messi...@gmail.com>:

More bug fixes have been merged to master now. (auto elo is still not fixed...).

To view this discussion visit https://groups.google.com/d/msgid/picochess/89a0c911-67ad-450b-9663-2da69aa166d7n%40googlegroups.com.

[Johan Sjöblom]

This wayland window switching using ydotool is now also merged to master branch.