<s>
The	O
Universal	B-General_Concept
Chess	I-General_Concept
Interface	I-General_Concept
(	O
UCI	O
)	O
is	O
an	O
open	O
communication	O
protocol	O
that	O
enables	O
chess	B-Application
engines	I-Application
to	O
communicate	O
with	O
user	B-Application
interfaces	I-Application
.	O
</s>
<s>
Designed	O
by	O
Rudolf	O
Huber	O
and	O
Stefan	O
Meyer-Kahlen	O
,	O
the	O
author	O
of	O
Shredder	B-Application
,	O
UCI	O
rivals	O
the	O
older	O
"	O
Chess	B-Application
Engine	I-Application
Communication	O
Protocol	O
"	O
introduced	O
with	O
XBoard/WinBoard	B-Application
.	O
</s>
<s>
In	O
2002	O
,	O
Chessbase	O
,	O
the	O
chess	O
software	O
company	O
which	O
markets	O
Fritz	B-Application
,	O
began	O
to	O
support	O
UCI	O
,	O
which	O
had	O
previously	O
been	O
supported	O
by	O
only	O
a	O
few	O
interfaces	O
and	O
engines	O
.	O
</s>
<s>
By	O
design	O
,	O
UCI	O
assigns	O
some	O
tasks	O
to	O
the	O
user	B-Application
interface	I-Application
(	O
i.e.	O
,	O
presentation	O
layer	O
)	O
which	O
have	O
traditionally	O
been	O
handled	O
by	O
the	O
engine	O
(	O
at	O
the	O
business	O
layer	O
)	O
itself	O
.	O
</s>
<s>
Most	O
notably	O
,	O
the	O
opening	O
book	O
is	O
usually	O
expected	O
to	O
be	O
handled	O
by	O
the	O
UI	B-Application
,	O
by	O
simply	O
selecting	O
moves	O
to	O
play	O
until	O
it	O
is	O
out	O
of	O
book	O
,	O
and	O
only	O
then	O
starting	O
up	O
the	O
engine	O
for	O
calculation	O
in	O
the	O
resulting	O
position	O
.	O
</s>
<s>
While	O
the	O
UI	B-Application
can	O
also	O
take	O
responsibility	O
for	O
handling	O
endgame	O
tablebases	O
,	O
this	O
is	O
arguably	O
better	O
handled	O
in	O
the	O
engine	O
itself	O
,	O
as	O
having	O
tablebase	O
information	O
can	O
be	O
useful	O
for	O
considering	O
possible	O
future	O
positions	O
.	O
</s>
<s>
Stefan-Meyer	O
Kahlen	O
's	O
UCI	O
protocol	O
in	O
Shredder	B-Application
uses	O
a	O
variation	O
of	O
long	O
algebraic	O
notation	O
for	O
moves	O
.	O
</s>
<s>
Engines	O
that	O
have	O
implemented	O
uci_elo	O
include	O
Delfi	B-Application
,	O
Fritz	B-Application
,	O
Hiarcs	B-Application
,	O
Houdini	B-Application
,	O
Junior	B-Application
,	O
Rybka	B-Application
,	O
Shredder	B-Application
,	O
Sjeng	B-Application
and	O
Stockfish	B-Application
.	O
</s>
<s>
The	O
XBoard	B-Application
CECP	O
is	O
said	O
to	O
require	O
far	O
fewer	O
changes	O
to	O
support	O
variants	O
.	O
</s>
