<s>
GNU	B-Application
Go	I-Application
is	O
a	O
free	B-Application
software	I-Application
program	O
by	O
the	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
that	O
plays	O
Go	O
.	O
</s>
<s>
Its	O
source	O
code	O
is	O
quite	O
portable	O
,	O
and	O
can	O
be	O
easily	O
compiled	O
for	O
Linux	B-Application
,	O
as	O
well	O
as	O
other	O
Unix-like	O
systems	O
,	O
Microsoft	B-Application
Windows	I-Application
and	O
macOS	B-Application
;	O
ports	O
exist	O
for	O
other	O
platforms	O
.	O
</s>
<s>
At	O
this	O
level	O
of	O
performance	O
,	O
GnuGo	B-Application
was	O
between	O
six	O
and	O
seven	O
stones	O
weaker	O
than	O
the	O
top	O
commercial	O
programs	O
on	O
good	O
hardware	O
as	O
of	O
early	O
2009	O
,	O
but	O
comparable	O
in	O
strength	O
to	O
the	O
strongest	O
programs	O
not	O
using	O
Monte	B-Algorithm
Carlo	I-Algorithm
methods	I-Algorithm
.	O
</s>
<s>
It	O
did	O
well	O
at	O
many	O
computer	B-Application
Go	I-Application
tournaments	O
.	O
</s>
<s>
Although	O
ASCII-based	O
,	O
GNU	B-Application
Go	I-Application
supports	O
two	O
protocols	O
—	O
the	O
Go	O
Modem	O
Protocol	O
and	O
the	O
Go	B-Application
Text	I-Application
Protocol	I-Application
—	O
by	O
which	O
GUIs	B-Application
can	O
interface	O
with	O
it	O
to	O
give	O
a	O
graphical	O
display	O
.	O
</s>
<s>
Several	O
such	O
GUIs	B-Application
exist	O
.	O
</s>
<s>
GTP	O
also	O
allows	O
it	O
to	O
play	O
online	O
on	O
Go	O
servers	O
(	O
through	O
the	O
use	O
of	O
bridge	O
programs	O
)	O
,	O
and	O
copies	O
can	O
be	O
found	O
running	O
on	O
NNGS	O
,	O
KGS	B-Application
,	O
and	O
probably	O
others	O
.	O
</s>
<s>
The	O
current	O
(	O
stable	O
)	O
version	O
of	O
GNU	B-Application
Go	I-Application
is	O
3.8	O
.	O
</s>
<s>
There	O
is	O
also	O
an	O
experimental	O
feature	O
for	O
using	O
Monte	B-Algorithm
Carlo	I-Algorithm
methods	I-Algorithm
for	O
9×9	O
board	O
play	O
.	O
</s>
<s>
A	O
version	O
called	O
Pocket	O
GNU	B-Application
Go	I-Application
,	O
based	O
on	O
GNU	B-Application
Go	I-Application
2.6	O
,	O
is	O
available	O
for	O
the	O
Windows	B-Operating_System
CE	I-Operating_System
operating	O
system	O
(	O
Pocket	B-Device
PC	I-Device
)	O
.	O
</s>
<s>
Versions	O
based	O
on	O
the	O
much	O
weaker	O
1.2	O
engine	O
also	O
exist	O
for	O
the	O
Game	B-Device
Boy	I-Device
Advance	I-Device
and	O
Palm	B-Device
Pilot	I-Device
.	O
</s>
