<s>
Chinook	B-General_Concept
is	O
a	O
computer	B-Application
program	I-Application
that	O
plays	O
checkers	O
(	O
also	O
known	O
as	O
draughts	O
)	O
.	O
</s>
<s>
All	O
of	O
Chinook	B-General_Concept
's	O
knowledge	O
was	O
programmed	O
by	O
its	O
creators	O
,	O
rather	O
than	O
learned	O
using	O
an	O
artificial	B-Application
intelligence	I-Application
system	O
.	O
</s>
<s>
Chinook	B-General_Concept
is	O
the	O
first	O
computer	B-Application
program	I-Application
to	O
win	O
the	O
world	O
champion	O
title	O
in	O
a	O
competition	O
against	O
humans	O
.	O
</s>
<s>
Tinsley	O
won	O
with	O
four	O
wins	O
to	O
Chinook	B-General_Concept
's	O
two	O
,	O
with	O
33	O
draws	O
.	O
</s>
<s>
In	O
a	O
rematch	O
,	O
Chinook	B-General_Concept
was	O
declared	O
the	O
Man-Machine	O
World	O
Champion	O
in	O
checkers	O
in	O
1994	O
in	O
a	O
match	O
against	O
Marion	O
Tinsley	O
after	O
six	O
drawn	O
games	O
,	O
and	O
Tinsley	O
's	O
withdrawal	O
due	O
to	O
pancreatic	O
cancer	O
.	O
</s>
<s>
While	O
Chinook	B-General_Concept
became	O
the	O
world	O
champion	O
,	O
it	O
never	O
defeated	O
the	O
best	O
checkers	O
player	O
of	O
all	O
time	O
,	O
Tinsley	O
,	O
who	O
was	O
significantly	O
superior	O
to	O
even	O
his	O
closest	O
peer	O
.	O
</s>
<s>
In	O
1995	O
,	O
Chinook	B-General_Concept
defended	O
its	O
man-machine	O
title	O
against	O
Don	O
Lafferty	O
in	O
a	O
32-game	O
match	O
.	O
</s>
<s>
The	O
final	O
score	O
was	O
1	O
–	O
0	O
with	O
31	O
draws	O
for	O
Chinook	B-General_Concept
over	O
Lafferty	O
.	O
</s>
<s>
After	O
the	O
match	O
,	O
Jonathan	O
Schaeffer	O
decided	O
not	O
to	O
let	O
Chinook	B-General_Concept
compete	O
any	O
more	O
,	O
but	O
instead	O
try	O
to	O
solve	O
checkers	O
.	O
</s>
<s>
Chinook	B-General_Concept
's	O
program	O
algorithm	O
includes	O
an	O
opening	O
book	O
,	O
a	O
library	O
of	O
opening	O
moves	O
from	O
games	O
played	O
by	O
grandmasters	O
;	O
a	O
deep	O
search	O
algorithm	O
;	O
a	O
good	O
move	O
evaluation	O
function	O
;	O
and	O
an	O
end-game	O
database	O
for	O
all	O
positions	O
with	O
eight	O
pieces	O
or	O
fewer	O
.	O
</s>
<s>
All	O
of	O
Chinook	B-General_Concept
's	O
knowledge	O
was	O
programmed	O
by	O
its	O
creators	O
,	O
rather	O
than	O
learned	O
with	O
artificial	B-Application
intelligence	I-Application
.	I-Application
</s>
<s>
1997	O
-	O
Jonathan	O
Schaeffer	O
writes	O
a	O
book	O
about	O
Chinook	B-General_Concept
called	O
One	O
Jump	O
Ahead	O
:	O
Challenging	O
Human	O
Supremacy	O
in	O
Checkers	O
.	O
</s>
<s>
May	O
24	O
,	O
2003	O
-	O
Chinook	B-General_Concept
completes	O
its	O
10	O
piece	O
database	O
with	O
5	O
pieces	O
on	O
each	O
side	O
.	O
</s>
<s>
August	O
2	O
,	O
2004	O
-	O
The	O
Chinook	B-General_Concept
team	O
announces	O
that	O
the	O
tournament-opening	O
in	O
checkers	O
called	O
the	O
White	O
Doctor	O
(	O
10	O
–	O
14	O
22	O
–	O
18	O
12	O
–	O
16	O
)	O
is	O
proven	O
to	O
be	O
a	O
draw	O
.	O
</s>
<s>
January	O
18	O
,	O
2006	O
-	O
The	O
Chinook	B-General_Concept
team	O
announces	O
that	O
the	O
09	O
–	O
13	O
21	O
–	O
17	O
05	O
–	O
09	O
opening	O
is	O
proven	O
to	O
be	O
a	O
draw	O
.	O
</s>
<s>
April	O
18	O
,	O
2006	O
-	O
The	O
Chinook	B-General_Concept
team	O
announces	O
that	O
the	O
09	O
–	O
13	O
22	O
–	O
17	O
13	O
–	O
22	O
opening	O
is	O
proven	O
to	O
be	O
a	O
draw	O
.	O
</s>
