<s>
Stockfish	B-Application
is	O
a	O
free	B-License
and	I-License
open-source	I-License
chess	B-Application
engine	I-Application
,	O
commonly	O
used	O
to	O
calculate	O
the	O
optimal	O
move	O
in	O
various	O
chess	B-Application
scenarios	O
needed	O
for	O
a	O
checkmate	O
.	O
</s>
<s>
It	O
is	O
available	O
for	O
various	O
desktop	O
and	O
mobile	O
platforms	O
and	O
can	O
be	O
used	O
in	O
chess	B-Application
software	I-Application
through	O
the	O
Universal	B-General_Concept
Chess	I-General_Concept
Interface	I-General_Concept
.	O
</s>
<s>
Stockfish	B-Application
has	O
consistently	O
ranked	O
first	O
or	O
near	O
the	O
top	O
of	O
most	O
chess-engine	O
rating	O
lists	O
and	O
,	O
as	O
of	O
April	O
2023	O
,	O
is	O
the	O
strongest	O
CPU	O
chess	B-Application
engine	I-Application
in	O
the	O
world	O
.	O
</s>
<s>
It	O
has	O
won	O
the	O
Top	O
Chess	B-Application
Engine	I-Application
Championship	O
13	O
times	O
and	O
the	O
Chess.com	B-Application
Computer	B-Application
Chess	I-Application
Championship	O
19	O
times	O
.	O
</s>
<s>
Stockfish	B-Application
is	O
developed	O
by	O
Tord	O
Romstad	O
,	O
Marco	O
Costalba	O
,	O
Joona	O
Kiiski	O
,	O
Gary	O
Linscott	O
,	O
Stéphane	O
Nicolet	O
,	O
Stefan	O
Geschwentner	O
,	O
and	O
Joost	O
VandeVondele	O
,	O
with	O
many	O
contributions	O
from	O
a	O
community	O
of	O
open-source	O
developers	O
.	O
</s>
<s>
It	O
is	O
derived	O
from	O
Glaurung	B-Application
,	O
an	O
open-source	O
engine	O
by	O
Tord	O
Romstad	O
released	O
in	O
2004	O
.	O
</s>
<s>
Stockfish	B-Application
can	O
use	O
up	O
to	O
1024	O
CPU	O
threads	O
in	O
multiprocessor	B-Operating_System
systems	O
.	O
</s>
<s>
The	O
maximal	O
size	O
of	O
its	O
transposition	B-General_Concept
table	I-General_Concept
is	O
32	O
TB	O
.	O
</s>
<s>
Stockfish	B-Application
implements	O
an	O
advanced	O
alpha	B-Algorithm
–	I-Algorithm
beta	I-Algorithm
search	I-Algorithm
and	O
uses	O
bitboards	B-Application
.	O
</s>
<s>
Compared	O
to	O
other	O
engines	O
,	O
it	O
is	O
characterized	O
by	O
its	O
great	O
search	O
depth	O
,	O
due	O
in	O
part	O
to	O
more	O
aggressive	O
pruning	B-Algorithm
and	O
late	B-Algorithm
move	I-Algorithm
reductions	I-Algorithm
.	O
</s>
<s>
,	O
Stockfish	B-Application
15.1	O
(	O
4-threaded	O
)	O
achieves	O
an	O
Elo	O
rating	O
of	O
3532	O
on	O
the	O
CCRL	O
40/15	O
benchmark	O
.	O
</s>
<s>
Stockfish	B-Application
supports	O
Chess960	O
,	O
which	O
is	O
one	O
feature	O
that	O
was	O
inherited	O
from	O
Glaurung	B-Application
.	O
</s>
<s>
The	O
Syzygy	O
tablebase	O
support	O
,	O
previously	O
available	O
in	O
a	O
fork	B-Application
maintained	O
by	O
Ronald	O
de	O
Man	O
,	O
was	O
integrated	O
into	O
Stockfish	B-Application
in	O
2014	O
.	O
</s>
<s>
Stockfish	B-Application
has	O
been	O
a	O
very	O
popular	O
engine	O
on	O
various	O
platforms	O
.	O
</s>
<s>
On	O
desktop	O
,	O
it	O
is	O
the	O
default	O
chess	B-Application
engine	I-Application
bundled	O
with	O
the	O
Internet	O
Chess	B-Application
Club	O
interface	O
programs	O
BlitzIn	O
and	O
Dasher	O
.	O
</s>
<s>
On	O
mobile	O
,	O
it	O
has	O
been	O
bundled	O
with	O
the	O
Stockfish	B-Application
app	O
,	O
SmallFish	O
and	O
Droidfish	O
.	O
</s>
<s>
Other	O
Stockfish-compatible	O
graphical	B-Application
user	I-Application
interfaces	I-Application
(	O
GUIs	B-Application
)	O
include	O
Fritz	B-Application
,	O
Arena	O
,	O
Stockfish	B-Application
for	O
Mac	O
,	O
and	O
PyChess	B-Language
.	O
</s>
<s>
Stockfish	B-Application
can	O
be	O
compiled	O
to	O
WebAssembly	B-Language
or	O
JavaScript	B-Language
,	O
allowing	O
it	O
to	O
run	O
in	O
the	O
browser	O
.	O
</s>
<s>
Both	O
chess.com	B-Application
and	O
Lichess	O
provide	O
Stockfish	B-Application
in	O
this	O
form	O
in	O
addition	O
to	O
a	O
server-side	O
program	O
.	O
</s>
<s>
Release	O
versions	O
and	O
development	O
versions	O
are	O
available	O
as	O
C++	B-Language
source	O
code	O
and	O
as	O
precompiled	O
versions	O
for	O
Microsoft	B-Application
Windows	I-Application
,	O
macOS	B-Application
,	O
Linux	B-Application
32-bit/64	O
-bit	O
and	O
Android	B-Application
.	O
</s>
<s>
The	O
program	O
originated	O
from	O
Glaurung	B-Application
,	O
an	O
open-source	O
chess	B-Application
engine	I-Application
created	O
by	O
Romstad	O
and	O
first	O
released	O
in	O
2004	O
.	O
</s>
<s>
Four	O
years	O
later	O
,	O
Costalba	O
,	O
inspired	O
by	O
the	O
strong	O
open-source	O
engine	O
,	O
decided	O
to	O
fork	B-Application
the	O
project	O
.	O
</s>
<s>
He	O
named	O
it	O
Stockfish	B-Application
because	O
it	O
was	O
"	O
produced	O
in	O
Norway	O
and	O
cooked	O
in	O
Italy	O
"	O
(	O
Romstad	O
is	O
Norwegian	O
,	O
Costalba	O
is	O
Italian	O
)	O
.	O
</s>
<s>
The	O
first	O
version	O
,	O
Stockfish	B-Application
1.0	O
,	O
was	O
released	O
in	O
November	O
2008	O
.	O
</s>
<s>
For	O
a	O
while	O
,	O
new	O
ideas	O
and	O
code	O
changes	O
were	O
transferred	O
between	O
the	O
two	O
programs	O
in	O
both	O
directions	O
,	O
until	O
Romstad	O
decided	O
to	O
discontinue	O
Glaurung	B-Application
in	O
favor	O
of	O
Stockfish	B-Application
,	O
which	O
was	O
the	O
more	O
advanced	O
engine	O
at	O
the	O
time	O
.	O
</s>
<s>
The	O
last	O
Glaurung	B-Application
version	O
(	O
2.2	O
)	O
was	O
released	O
in	O
December	O
2008	O
.	O
</s>
<s>
Around	O
2011	O
,	O
Romstad	O
decided	O
to	O
abandon	O
his	O
involvement	O
with	O
Stockfish	B-Application
in	O
order	O
to	O
spend	O
more	O
time	O
on	O
his	O
new	O
iOS	B-Operating_System
chess	B-Application
app	O
.	O
</s>
<s>
On	O
18	O
June	O
2014	O
Marco	O
Costalba	O
announced	O
that	O
he	O
had	O
"	O
decided	O
to	O
step	O
down	O
as	O
Stockfish	B-Application
maintainer	O
"	O
and	O
asked	O
that	O
the	O
community	O
create	O
a	O
fork	B-Application
of	O
the	O
current	O
version	O
and	O
continue	O
its	O
development	O
.	O
</s>
<s>
An	O
official	O
repository	O
,	O
managed	O
by	O
a	O
volunteer	O
group	O
of	O
core	O
Stockfish	B-Application
developers	O
,	O
was	O
created	O
soon	O
after	O
and	O
currently	O
manages	O
the	O
development	O
of	O
the	O
project	O
.	O
</s>
<s>
Since	O
2013	O
,	O
Stockfish	B-Application
has	O
been	O
developed	O
using	O
a	O
distributed	B-Architecture
testing	O
framework	O
named	O
Fishtest	O
,	O
where	O
volunteers	O
can	O
donate	O
CPU	O
time	O
for	O
testing	O
improvements	O
to	O
the	O
program	O
.	O
</s>
<s>
Tests	O
on	O
the	O
framework	O
are	O
verified	O
using	O
the	O
chi-squared	B-General_Concept
test	I-General_Concept
,	O
and	O
only	O
if	O
the	O
results	O
are	O
statistically	O
significant	O
are	O
they	O
deemed	O
reliable	O
and	O
used	O
to	O
revise	O
the	O
software	O
code	O
.	O
</s>
<s>
After	O
the	O
inception	O
of	O
Fishtest	O
,	O
Stockfish	B-Application
experienced	O
an	O
explosive	O
growth	O
of	O
120	O
Elo	O
points	O
in	O
just	O
12	O
months	O
,	O
propelling	O
it	O
to	O
the	O
top	O
of	O
all	O
major	O
rating	O
lists	O
.	O
</s>
<s>
In	O
Stockfish	B-Application
7	O
,	O
Fishtest	O
author	O
Gary	O
Linscott	O
was	O
added	O
to	O
the	O
official	O
list	O
of	O
authors	O
in	O
acknowledgement	O
of	O
his	O
contribution	O
to	O
Stockfish	B-Application
's	O
strength	O
.	O
</s>
<s>
As	O
of	O
April	O
2023	O
,	O
the	O
framework	O
has	O
used	O
a	O
total	O
of	O
more	O
than	O
9800	O
years	O
of	O
CPU	O
time	O
to	O
play	O
over	O
5.8	O
billion	O
chess	B-Application
games	O
.	O
</s>
<s>
In	O
June	O
2020	O
,	O
an	O
efficiently	B-General_Concept
updatable	I-General_Concept
neural	I-General_Concept
network	I-General_Concept
(	O
NNUE	B-General_Concept
)	O
fork	B-Application
introduced	O
by	O
computer	B-Application
shogi	I-Application
programmers	O
called	O
Stockfish	B-Application
NNUE	B-General_Concept
was	O
discussed	O
by	O
developers	O
.	O
</s>
<s>
In	O
July	O
2020	O
chess	B-Application
news	O
reported	O
that	O
Stockfish	B-Application
NNUE	B-General_Concept
had	O
"	O
broken	O
new	O
ground	O
in	O
computer	B-Application
chess	I-Application
by	O
incorporating	O
a	O
neural	O
network	O
into	O
the	O
already	O
incredibly	O
powerful	O
Stockfish	B-Application
chess	B-Application
engine.	O
"	O
</s>
<s>
A	O
NNUE	B-General_Concept
merge	B-General_Concept
into	O
Stockfish	B-Application
was	O
then	O
announced	O
and	O
development	O
builds	O
became	O
available	O
.	O
</s>
<s>
On	O
2	O
September	O
2020	O
,	O
the	O
twelfth	O
version	O
of	O
Stockfish	B-Application
was	O
released	O
,	O
incorporating	O
the	O
aforementioned	O
neural	O
network	O
improvement	O
.	O
</s>
<s>
Stockfish	B-Application
is	O
a	O
TCEC	O
multiple-time	O
champion	O
and	O
the	O
current	O
leader	O
in	O
trophy	O
count	O
.	O
</s>
<s>
Ever	O
since	O
TCEC	O
restarted	O
in	O
2013	O
,	O
Stockfish	B-Application
has	O
finished	O
first	O
or	O
second	O
in	O
every	O
season	O
except	O
one	O
.	O
</s>
<s>
In	O
TCEC	O
Season	O
4	O
and	O
5	O
,	O
Stockfish	B-Application
finished	O
runner-up	O
,	O
with	O
Superfinal	O
scores	O
of	O
23	O
–	O
25	O
first	O
against	O
Houdini	B-Application
3	I-Application
and	O
later	O
against	O
Komodo	B-Application
1142	O
.	O
</s>
<s>
Season	O
5	O
was	O
notable	O
for	O
the	O
winning	O
Komodo	B-Application
team	O
as	O
they	O
accepted	O
the	O
award	O
posthumously	O
for	O
the	O
program	O
's	O
creator	O
Don	O
Dailey	O
,	O
who	O
succumbed	O
to	O
an	O
illness	O
during	O
the	O
final	O
stage	O
of	O
the	O
event	O
.	O
</s>
<s>
In	O
his	O
honor	O
,	O
the	O
version	O
of	O
Stockfish	B-Application
that	O
was	O
released	O
shortly	O
after	O
that	O
season	O
was	O
named	O
"	O
Stockfish	B-Application
DD	I-Application
"	O
.	O
</s>
<s>
On	O
30	O
May	O
2014	O
,	O
Stockfish	B-Application
170514	O
(	O
a	O
development	O
version	O
of	O
Stockfish	B-Application
5	O
with	O
tablebase	O
support	O
)	O
convincingly	O
won	O
TCEC	O
Season	O
6	O
,	O
scoring	O
35.5	O
–	O
28.5	O
against	O
Komodo	B-Application
7x	O
in	O
the	O
Superfinal	O
.	O
</s>
<s>
Stockfish	B-Application
5	O
was	O
released	O
the	O
following	O
day	O
.	O
</s>
<s>
In	O
TCEC	O
Season	O
7	O
,	O
Stockfish	B-Application
again	O
made	O
the	O
Superfinal	O
,	O
but	O
lost	O
to	O
Komodo	B-Application
with	O
the	O
score	O
of	O
30.5	O
–	O
33.5	O
.	O
</s>
<s>
In	O
TCEC	O
Season	O
8	O
,	O
despite	O
losses	O
on	O
time	O
caused	O
by	O
buggy	O
code	O
,	O
Stockfish	B-Application
nevertheless	O
qualified	O
once	O
more	O
for	O
the	O
Superfinal	O
,	O
but	O
lost	O
the	O
ensuing	O
100-game	O
match	O
46.5	O
–	O
53.5	O
to	O
Komodo	B-Application
.	O
</s>
<s>
In	O
Season	O
9	O
,	O
Stockfish	B-Application
defeated	O
Houdini	B-Application
5	O
with	O
a	O
score	O
of	O
54.5	O
versus	O
45.5	O
.	O
</s>
<s>
Stockfish	B-Application
finished	O
third	O
during	O
season	O
10	O
of	O
TCEC	O
,	O
the	O
only	O
season	O
since	O
2013	O
in	O
which	O
Stockfish	B-Application
had	O
failed	O
to	O
qualify	O
for	O
the	O
superfinal	O
.	O
</s>
<s>
After	O
this	O
technical	O
elimination	O
,	O
Stockfish	B-Application
went	O
on	O
a	O
long	O
winning	O
streak	O
,	O
winning	O
seasons	O
11	O
(	O
59	O
vs.	O
41	O
against	O
Houdini	B-Application
6.03	O
)	O
,	O
12	O
(	O
60	O
vs.	O
40	O
against	O
Komodo	B-Application
12.1.1	O
)	O
,	O
and	O
13	O
(	O
55	O
vs.	O
45	O
against	O
Komodo	B-Application
2155.00	O
)	O
convincingly	O
.	O
</s>
<s>
In	O
Season	O
14	O
,	O
Stockfish	B-Application
faced	O
a	O
new	O
challenger	O
in	O
Leela	B-Application
Chess	I-Application
Zero	I-Application
,	O
but	O
managed	O
to	O
eke	O
out	O
a	O
win	O
by	O
one	O
game	O
(	O
50.5	O
–	O
49.5	O
)	O
.	O
</s>
<s>
Its	O
winning	O
streak	O
was	O
finally	O
ended	O
in	O
season	O
15	O
,	O
when	O
Leela	O
qualified	O
again	O
and	O
won	O
53.5	O
–	O
46.5	O
,	O
but	O
Stockfish	B-Application
promptly	O
won	O
season	O
16	O
,	O
defeating	O
AllieStein	O
54.5	O
–	O
45.5	O
,	O
after	O
Leela	O
failed	O
to	O
qualify	O
for	O
the	O
superfinal	O
.	O
</s>
<s>
In	O
season	O
17	O
,	O
Stockfish	B-Application
faced	O
Leela	O
again	O
in	O
the	O
superfinal	O
,	O
losing	O
52.5	O
–	O
47.5	O
.	O
</s>
<s>
However	O
,	O
Stockfish	B-Application
has	O
won	O
every	O
superfinal	O
since	O
:	O
beating	O
Leela	O
53.5	O
–	O
46.5	O
in	O
season	O
18	O
,	O
54.5	O
–	O
45.5	O
in	O
season	O
19	O
,	O
53	O
–	O
47	O
in	O
season	O
20	O
,	O
and	O
56	O
–	O
44	O
in	O
season	O
21	O
.	O
</s>
<s>
In	O
Season	O
22	O
,	O
Komodo	B-Application
Dragon	I-Application
beat	O
out	O
Leela	O
to	O
qualify	O
for	O
the	O
superfinal	O
,	O
but	O
was	O
crushed	O
by	O
Stockfish	B-Application
59.5-40.5	O
.	O
</s>
<s>
Stockfish	B-Application
did	O
not	O
lose	O
an	O
opening	O
pair	O
in	O
this	O
match	O
.	O
</s>
<s>
Leela	O
made	O
the	O
superfinal	O
in	O
Season	O
23	O
,	O
but	O
was	O
also	O
crushed	O
by	O
Stockfish	B-Application
58.5-41.5	O
.	O
</s>
<s>
Stockfish	B-Application
also	O
took	O
part	O
in	O
the	O
TCEC	O
cup	O
,	O
winning	O
the	O
first	O
edition	O
,	O
but	O
was	O
surprisingly	O
upset	O
by	O
Houdini	B-Application
in	O
the	O
semifinals	O
of	O
the	O
second	O
edition	O
.	O
</s>
<s>
Stockfish	B-Application
recovered	O
to	O
beat	O
Komodo	B-Application
in	O
the	O
third-place	O
playoff	O
.	O
</s>
<s>
In	O
the	O
third	O
edition	O
,	O
Stockfish	B-Application
made	O
it	O
to	O
the	O
finals	O
,	O
but	O
was	O
defeated	O
by	O
Leela	B-Application
Chess	I-Application
Zero	I-Application
after	O
blundering	O
in	O
a	O
7-man	O
endgame	O
tablebase	O
draw	O
.	O
</s>
<s>
Ever	O
since	O
chess.com	B-Application
hosted	O
its	O
first	O
Chess.com	B-Application
Computer	B-Application
Chess	I-Application
Championship	O
in	O
2018	O
,	O
Stockfish	B-Application
has	O
been	O
the	O
most	O
successful	O
engine	O
.	O
</s>
<s>
Since	O
then	O
,	O
its	O
dominance	O
has	O
come	O
under	O
threat	O
from	O
the	O
neural-network	O
engines	O
Leelenstein	O
and	O
Leela	B-Application
Chess	I-Application
Zero	I-Application
,	O
but	O
it	O
has	O
continued	O
to	O
perform	O
well	O
,	O
reaching	O
at	O
least	O
the	O
superfinal	O
in	O
every	O
edition	O
up	O
to	O
CCC11	O
.	O
</s>
<s>
CCC12	O
had	O
for	O
the	O
first	O
time	O
a	O
knockout	O
format	O
,	O
with	O
seeding	O
placing	O
CCC11	O
finalists	O
Stockfish	B-Application
and	O
Leela	O
in	O
the	O
same	O
half	O
.	O
</s>
<s>
Leela	O
eliminated	O
Stockfish	B-Application
in	O
the	O
semi-finals	O
.	O
</s>
<s>
However	O
,	O
a	O
post-tournament	O
match	O
against	O
the	O
loser	O
of	O
the	O
final	O
,	O
Leelenstein	O
,	O
saw	O
Stockfish	B-Application
winning	O
in	O
the	O
same	O
format	O
as	O
the	O
main	O
event	O
.	O
</s>
<s>
Stockfish	B-Application
's	O
strength	O
relative	O
to	O
the	O
best	O
human	O
chess	B-Application
players	O
was	O
most	O
apparent	O
in	O
a	O
handicap	O
match	O
with	O
grandmaster	O
Hikaru	O
Nakamura	O
(	O
2798-rated	O
)	O
in	O
August	O
2014	O
.	O
</s>
<s>
In	O
the	O
first	O
two	O
games	O
of	O
the	O
match	O
,	O
Nakamura	O
had	O
the	O
assistance	O
of	O
an	O
older	O
version	O
of	O
Rybka	B-Application
,	O
and	O
in	O
the	O
next	O
two	O
games	O
,	O
he	O
received	O
White	O
with	O
pawn	O
odds	O
but	O
no	O
assistance	O
.	O
</s>
<s>
Nakamura	O
was	O
the	O
world	O
's	O
fifth-best	O
human	O
chess	B-Application
player	O
at	O
the	O
time	O
of	O
the	O
match	O
,	O
while	O
Stockfish	B-Application
5	O
was	O
denied	O
use	O
of	O
its	O
opening	O
book	O
and	O
endgame	O
tablebase	O
.	O
</s>
<s>
Stockfish	B-Application
won	O
each	O
half	O
of	O
the	O
match	O
1.5	O
–	O
0.5	O
.	O
</s>
<s>
Both	O
of	O
Stockfish	B-Application
's	O
wins	O
arose	O
from	O
positions	O
in	O
which	O
Nakamura	O
,	O
as	O
is	O
typical	O
for	O
his	O
playing	O
style	O
,	O
pressed	O
for	O
a	O
win	O
instead	O
of	O
acquiescing	O
to	O
a	O
draw	O
.	O
</s>
<s>
In	O
December	O
2017	O
,	O
Stockfish	B-Application
8	O
was	O
used	O
as	O
a	O
benchmark	O
to	O
test	O
Google	B-Application
division	O
DeepMind	B-Application
's	O
AlphaZero	B-Application
,	O
with	O
each	O
engine	O
supported	O
by	O
different	O
hardware	O
.	O
</s>
<s>
AlphaZero	B-Application
was	O
trained	O
through	O
self-play	O
for	O
a	O
total	O
of	O
nine	O
hours	O
,	O
and	O
reached	O
Stockfish	B-Application
's	O
level	O
after	O
just	O
four	O
.	O
</s>
<s>
In	O
100	O
games	O
from	O
the	O
normal	O
starting	O
position	O
,	O
AlphaZero	B-Application
won	O
25	O
games	O
as	O
White	O
,	O
won	O
3	O
as	O
Black	O
,	O
and	O
drew	O
the	O
remaining	O
72	O
,	O
with	O
0	O
losses	O
.	O
</s>
<s>
AlphaZero	B-Application
also	O
played	O
twelve	O
100-game	O
matches	O
against	O
Stockfish	B-Application
starting	O
from	O
twelve	O
popular	O
openings	O
for	O
a	O
final	O
score	O
of	O
290	O
wins	O
,	O
886	O
draws	O
and	O
24	O
losses	O
,	O
for	O
a	O
point	O
score	O
of	O
733:467	O
.	O
</s>
<s>
AlphaZero	B-Application
's	O
victory	O
over	O
Stockfish	B-Application
sparked	O
a	O
flurry	O
of	O
activity	O
in	O
the	O
computer	B-Application
chess	I-Application
community	O
,	O
leading	O
to	O
a	O
new	O
open-source	O
engine	O
aimed	O
at	O
replicating	O
AlphaZero	B-Application
,	O
known	O
as	O
Leela	B-Application
Chess	I-Application
Zero	I-Application
.	O
</s>
<s>
By	O
January	O
2019	O
,	O
Leela	O
was	O
able	O
to	O
defeat	O
the	O
version	O
of	O
Stockfish	B-Application
that	O
played	O
AlphaZero	B-Application
(	O
Stockfish	B-Application
8	O
)	O
in	O
a	O
100-game	O
match	O
.	O
</s>
<s>
An	O
updated	O
version	O
of	O
Stockfish	B-Application
narrowly	O
defeated	O
Leela	B-Application
Chess	I-Application
Zero	I-Application
in	O
the	O
superfinal	O
of	O
the	O
14th	O
TCEC	O
season	O
,	O
50.5	O
–	O
49.5	O
( +10	O
=	O
81	O
−9	O
)	O
,	O
but	O
lost	O
the	O
superfinal	O
of	O
the	O
next	O
season	O
to	O
Leela	O
53.5	O
–	O
46.5	O
( +14	O
=	O
79	O
-7	O
)	O
.	O
</s>
<s>
The	O
two	O
engines	O
remain	O
very	O
close	O
in	O
strength	O
to	O
each	O
other	O
even	O
as	O
they	O
continue	O
to	O
improve	O
:	O
Leela	O
defeated	O
Stockfish	B-Application
in	O
the	O
superfinal	O
of	O
TCEC	O
Season	O
17	O
,	O
but	O
Stockfish	B-Application
won	O
TCEC	O
Season	O
18	O
,	O
TCEC	O
Season	O
19	O
,	O
TCEC	O
Season	O
20	O
,	O
and	O
TCEC	O
Season	O
21	O
,	O
each	O
time	O
defeating	O
Leela	O
in	O
the	O
superfinal	O
.	O
</s>
<s>
YaneuraOu	O
,	O
a	O
strong	O
shogi	O
engine	O
and	O
the	O
origin	O
of	O
NNUE	B-General_Concept
.	O
</s>
<s>
Speaks	O
USI	O
,	O
a	O
variant	O
of	O
UCI	B-General_Concept
for	O
shogi	O
.	O
</s>
<s>
Fairy	O
Stockfish	B-Application
,	O
a	O
version	O
modified	O
to	O
play	O
fairy	O
chess	B-Application
.	O
</s>
<s>
Runs	O
with	O
regional	O
variants	O
(	O
chess	B-Application
,	O
shogi	O
,	O
makruk	O
,	O
etc	O
.	O
)	O
</s>
<s>
Lichess	O
Stockfish	B-Application
,	O
a	O
version	O
for	O
playing	O
variants	O
without	O
fairy	O
pieces	O
.	O
</s>
<s>
Crystal	O
,	O
which	O
seeks	O
to	O
address	O
common	O
issues	O
with	O
chess	B-Application
engines	I-Application
such	O
as	O
positional	O
or	O
tactical	O
blindness	O
due	O
to	O
over	O
reductions	O
or	O
over	O
pruning	B-Algorithm
,	O
draw	O
blindness	O
due	O
to	O
the	O
move	O
horizon	O
and	O
displayed	O
principal	O
variation	O
reliability	O
.	O
</s>
<s>
Brainfish	O
,	O
which	O
contains	O
a	O
reduced	O
version	O
of	O
Cerebellum	O
,	O
a	O
chess	B-Application
opening	O
library	O
.	O
</s>
<s>
Fat	O
Titz	O
,	O
a	O
fork	B-Application
of	O
CFish	O
which	O
name	O
is	O
a	O
pun	O
of	O
Fat	O
Fritz	B-Application
2	O
with	O
a	O
HalfKAv2-2048x2-64-64-1	O
evaluation	O
network	O
,	O
which	O
contains	O
4	O
times	O
the	O
knowledge	O
of	O
Stockfish	B-Application
14	O
.	O
</s>
<s>
It	O
was	O
trained	O
partially	O
on	O
Lc0	B-Application
data	O
,	O
which	O
gives	O
a	O
unique	O
positional	O
style	O
,	O
while	O
still	O
preserving	O
the	O
tactical	O
sharpness	O
of	O
Stockfish	B-Application
.	O
</s>
<s>
Houdini	B-Application
6	O
,	O
an	O
alleged	O
Stockfish	B-Application
8	O
derivative	O
without	O
providing	O
the	O
sources	O
on	O
request	O
,	O
violating	O
the	O
GPL	B-License
license	I-License
.	O
</s>
<s>
Fat	O
Fritz	B-Application
2	O
,	O
an	O
alleged	O
Stockfish	B-Application
12	O
derivative	O
without	O
providing	O
the	O
sources	O
on	O
request	O
,	O
violating	O
the	O
GPL	B-License
license	I-License
.	O
</s>
