<s>
Deep	B-General_Concept
Blue	I-General_Concept
was	O
a	O
chess-playing	B-Application
expert	B-Application
system	I-Application
run	O
on	O
a	O
unique	O
purpose-built	O
IBM	O
supercomputer	B-Architecture
.	O
</s>
<s>
Development	O
began	O
in	O
1985	O
at	O
Carnegie	O
Mellon	O
University	O
under	O
the	O
name	O
ChipTest	B-General_Concept
.	O
</s>
<s>
It	O
then	O
moved	O
to	O
IBM	O
,	O
where	O
it	O
was	O
first	O
renamed	O
Deep	B-General_Concept
Thought	I-General_Concept
,	O
then	O
again	O
in	O
1989	O
to	O
Deep	B-General_Concept
Blue	I-General_Concept
.	O
</s>
<s>
Deep	B-General_Concept
Blue	I-General_Concept
's	O
victory	O
is	O
considered	O
a	O
milestone	O
in	O
the	O
history	O
of	O
artificial	B-Application
intelligence	I-Application
and	O
has	O
been	O
the	O
subject	O
of	O
several	O
books	O
and	O
films	O
.	O
</s>
<s>
While	O
a	O
doctoral	O
student	O
at	O
Carnegie	O
Mellon	O
University	O
,	O
Feng-hsiung	O
Hsu	O
began	O
development	O
of	O
a	O
chess-playing	B-Application
supercomputer	B-Architecture
under	O
the	O
name	O
ChipTest	B-General_Concept
.	O
</s>
<s>
The	O
machine	O
won	O
the	O
North	O
American	O
Computer	B-Application
Chess	I-Application
Championship	O
in	O
1987	O
and	O
Hsu	O
and	O
his	O
team	O
followed	O
up	O
with	O
a	O
successor	O
,	O
Deep	B-General_Concept
Thought	I-General_Concept
,	O
in	O
1988	O
.	O
</s>
<s>
After	O
receiving	O
his	O
doctorate	O
in	O
1989	O
,	O
Hsu	O
and	O
Murray	O
Campbell	O
joined	O
IBM	O
Research	O
to	O
continue	O
their	O
project	O
to	O
build	O
a	O
machine	O
that	O
could	O
defeat	O
a	O
world	O
chess	B-Application
champion	O
.	O
</s>
<s>
After	O
Deep	B-General_Concept
Thought	I-General_Concept
's	O
two-game	O
1989	O
loss	O
to	O
Kasparov	O
,	O
IBM	O
held	O
a	O
contest	O
to	O
rename	O
the	O
chess	B-Application
machine	O
:	O
the	O
winning	O
name	O
was	O
"	O
Deep	B-General_Concept
Blue	I-General_Concept
"	O
,	O
submitted	O
by	O
Peter	O
Fitzhugh	O
Brown	O
,	O
was	O
a	O
play	O
on	O
IBM	O
's	O
nickname	O
,	O
"	O
Big	O
Blue	O
"	O
.	O
</s>
<s>
After	O
a	O
scaled-down	O
version	O
of	O
Deep	B-General_Concept
Blue	I-General_Concept
played	O
Grandmaster	O
Joel	O
Benjamin	O
,	O
Hsu	O
and	O
Campbell	O
decided	O
that	O
Benjamin	O
was	O
the	O
expert	O
they	O
were	O
looking	O
for	O
to	O
help	O
develop	O
Deep	B-General_Concept
Blue	I-General_Concept
's	O
opening	O
book	O
,	O
so	O
hired	O
him	O
to	O
assist	O
with	O
the	O
preparations	O
for	O
Deep	B-General_Concept
Blue	I-General_Concept
's	O
matches	O
against	O
Garry	O
Kasparov	O
.	O
</s>
<s>
In	O
1995	O
,	O
a	O
Deep	B-General_Concept
Blue	I-General_Concept
prototype	O
played	O
in	O
the	O
eighth	O
World	O
Computer	B-Application
Chess	I-Application
Championship	O
,	O
playing	O
Wchess	B-Application
to	O
a	O
draw	O
before	O
ultimately	O
losing	O
to	O
Fritz	B-Application
in	O
round	O
five	O
,	O
despite	O
playing	O
as	O
White	O
.	O
</s>
<s>
In	O
1997	O
,	O
the	O
Chicago	O
Tribune	O
mistakenly	O
reported	O
that	O
Deep	B-General_Concept
Blue	I-General_Concept
had	O
been	O
sold	O
to	O
United	O
Airlines	O
,	O
a	O
confusion	O
based	O
upon	O
its	O
physical	O
resemblance	O
to	O
IBM	O
's	O
mainstream	O
RS6000/SP2	B-Device
systems	O
.	O
</s>
<s>
Today	O
,	O
one	O
of	O
the	O
two	O
racks	O
that	O
made	O
up	O
Deep	B-General_Concept
Blue	I-General_Concept
is	O
held	O
by	O
the	O
National	O
Museum	O
of	O
American	O
History	O
,	O
having	O
previously	O
been	O
displayed	O
in	O
an	O
exhibit	O
about	O
the	O
Information	O
Age	O
,	O
while	O
the	O
other	O
rack	O
was	O
acquired	O
by	O
the	O
Computer	O
History	O
Museum	O
in	O
1997	O
,	O
and	O
is	O
displayed	O
in	O
the	O
Revolution	O
exhibit	O
's	O
"	O
Artificial	B-Application
Intelligence	I-Application
and	O
Robotics	O
"	O
gallery	O
.	O
</s>
<s>
Several	O
books	O
were	O
written	O
about	O
Deep	B-General_Concept
Blue	I-General_Concept
,	O
among	O
them	O
Behind	O
Deep	B-General_Concept
Blue	I-General_Concept
:	O
Building	O
the	O
Computer	O
that	O
Defeated	O
the	O
World	O
Chess	B-Application
Champion	O
by	O
Deep	B-General_Concept
Blue	I-General_Concept
developer	O
Feng-hsiung	O
Hsu	O
.	O
</s>
<s>
Subsequent	O
to	O
its	O
predecessor	O
Deep	B-General_Concept
Thought	I-General_Concept
's	O
1989	O
loss	O
to	O
Garry	O
Kasparov	O
,	O
Deep	B-General_Concept
Blue	I-General_Concept
played	O
Kasparov	O
twice	O
more	O
.	O
</s>
<s>
In	O
the	O
first	O
game	O
of	O
the	O
first	O
match	O
,	O
which	O
took	O
place	O
from	O
10	O
to	O
17	O
February	O
1996	O
,	O
Deep	B-General_Concept
Blue	I-General_Concept
became	O
the	O
first	O
machine	O
to	O
win	O
a	O
chess	B-Application
game	O
against	O
a	O
reigning	O
world	O
champion	O
under	O
regular	O
time	O
controls	O
.	O
</s>
<s>
However	O
,	O
Kasparov	O
won	O
three	O
and	O
drew	O
two	O
of	O
the	O
following	O
five	O
games	O
,	O
beating	O
Deep	B-General_Concept
Blue	I-General_Concept
by	O
4	O
–	O
2	O
at	O
the	O
close	O
of	O
the	O
match	O
.	O
</s>
<s>
Deep	B-General_Concept
Blue	I-General_Concept
's	O
hardware	O
was	O
subsequently	O
upgraded	O
,	O
doubling	O
its	O
speed	O
before	O
it	O
faced	O
Kasparov	O
again	O
in	O
May	O
1997	O
,	O
when	O
it	O
won	O
the	O
six-game	O
rematch	O
3½	O
–	O
2½	O
.	O
</s>
<s>
Deep	B-General_Concept
Blue	I-General_Concept
won	O
the	O
deciding	O
game	O
after	O
Kasparov	O
failed	O
to	O
secure	O
his	O
position	O
in	O
the	O
opening	O
,	O
thereby	O
becoming	O
the	O
first	O
computer	O
system	O
to	O
defeat	O
a	O
reigning	O
world	O
champion	O
in	O
a	O
match	O
under	O
standard	O
chess	B-Application
tournament	O
time	O
controls	O
.	O
</s>
<s>
The	O
version	O
of	O
Deep	B-General_Concept
Blue	I-General_Concept
that	O
defeated	O
Kasparov	O
in	O
1997	O
typically	O
searched	O
to	O
a	O
depth	O
of	O
six	O
to	O
eight	O
moves	O
,	O
and	O
twenty	O
or	O
more	O
moves	O
in	O
some	O
situations	O
.	O
</s>
<s>
In	O
the	O
44th	O
move	O
of	O
the	O
first	O
game	O
of	O
their	O
second	O
match	O
,	O
unknown	O
to	O
Kasparov	O
,	O
a	O
bug	B-Error_Name
in	O
Deep	B-General_Concept
Blue	I-General_Concept
's	O
code	O
led	O
it	O
to	O
enter	O
an	O
unintentional	O
loop	O
,	O
which	O
it	O
exited	O
by	O
taking	O
a	O
randomly	O
selected	O
valid	O
move	O
.	O
</s>
<s>
Subsequently	O
,	O
Kasparov	O
experienced	O
a	O
decline	O
in	O
performance	O
in	O
the	O
following	O
game	O
,	O
though	O
he	O
denies	O
this	O
was	O
due	O
to	O
anxiety	O
in	O
the	O
wake	O
of	O
Deep	B-General_Concept
Blue	I-General_Concept
's	O
inscrutable	O
move	O
.	O
</s>
<s>
After	O
his	O
loss	O
,	O
Kasparov	O
said	O
that	O
he	O
sometimes	O
saw	O
unusual	O
creativity	O
in	O
the	O
machine	O
's	O
moves	O
,	O
suggesting	O
that	O
during	O
the	O
second	O
game	O
,	O
human	O
chess	B-Application
players	O
had	O
intervened	O
on	O
behalf	O
of	O
the	O
machine	O
.	O
</s>
<s>
Kasparov	O
demanded	O
a	O
rematch	O
,	O
but	O
IBM	O
had	O
dismantled	O
Deep	B-General_Concept
Blue	I-General_Concept
after	O
its	O
victory	O
and	O
refused	O
the	O
rematch	O
.	O
</s>
<s>
Kasparov	O
initially	O
called	O
Deep	B-General_Concept
Blue	I-General_Concept
an	O
"	O
alien	O
opponent	O
"	O
but	O
later	O
belittled	O
it	O
,	O
stating	O
that	O
it	O
was	O
"	O
as	O
intelligent	O
as	O
your	O
alarm	O
clock	O
"	O
.	O
</s>
<s>
According	O
to	O
Martin	O
Amis	O
,	O
two	O
grandmasters	O
who	O
played	O
Deep	B-General_Concept
Blue	I-General_Concept
agreed	O
that	O
it	O
was	O
"	O
like	O
a	O
wall	O
coming	O
at	O
you	O
"	O
.	O
</s>
<s>
Hsu	O
had	O
the	O
rights	O
to	O
use	O
the	O
Deep	B-General_Concept
Blue	I-General_Concept
design	O
independently	O
of	O
IBM	O
,	O
but	O
also	O
independently	O
declined	O
Kasparov	O
's	O
rematch	O
offer	O
.	O
</s>
<s>
In	O
the	O
film	O
,	O
some	O
interviewees	O
describe	O
IBM	O
's	O
investment	O
in	O
Deep	B-General_Concept
Blue	I-General_Concept
as	O
an	O
effort	O
to	O
boost	O
its	O
stock	O
value	O
.	O
</s>
<s>
Following	O
Deep	B-General_Concept
Blue	I-General_Concept
's	O
victory	O
,	O
AI	B-Application
specialist	O
Omar	O
Syed	O
designed	O
a	O
new	O
game	O
,	O
Arimaa	O
,	O
which	O
was	O
intended	O
to	O
be	O
very	O
simple	O
for	O
humans	O
but	O
very	O
difficult	O
for	O
computers	O
to	O
master	O
;	O
however	O
,	O
in	O
2015	O
,	O
computers	O
proved	O
capable	O
of	O
defeating	O
strong	O
Arimaa	O
players	O
.	O
</s>
<s>
Since	O
Deep	B-General_Concept
Blue	I-General_Concept
's	O
victory	O
,	O
computer	O
scientists	O
have	O
developed	O
software	O
for	O
other	O
complex	O
board	O
games	O
with	O
competitive	O
communities	O
.	O
</s>
<s>
AlphaGo	B-Application
defeated	O
top	O
Go	O
players	O
in	O
the	O
2010s	O
.	O
</s>
<s>
Computer	O
scientists	O
such	O
as	O
Deep	B-General_Concept
Blue	I-General_Concept
developer	O
Campbell	O
believed	O
that	O
playing	O
chess	B-Application
was	O
a	O
good	O
measurement	O
for	O
the	O
effectiveness	O
of	O
artificial	B-Application
intelligence	I-Application
,	O
and	O
by	O
beating	O
a	O
world	O
champion	O
chess	B-Application
player	O
,	O
IBM	O
showed	O
that	O
they	O
had	O
made	O
significant	O
progress	O
.	O
</s>
<s>
Deep	B-General_Concept
Blue	I-General_Concept
is	O
also	O
responsible	O
for	O
the	O
popularity	O
of	O
using	O
games	O
as	O
a	O
display	O
medium	O
for	O
artificial	B-Application
intelligence	I-Application
,	O
as	O
in	O
the	O
cases	O
of	O
IBM	B-Application
Watson	I-Application
or	O
AlphaGo	B-Application
.	O
</s>
<s>
While	O
Deep	B-General_Concept
Blue	I-General_Concept
,	O
with	O
its	O
capability	O
of	O
evaluating	O
200million	O
positions	O
per	O
second	O
,	O
was	O
the	O
first	O
computer	O
to	O
face	O
a	O
world	O
chess	B-Application
champion	O
in	O
a	O
formal	O
match	O
,	O
it	O
was	O
a	O
then-state-of-the-art	O
expert	B-Application
system	I-Application
,	O
relying	O
upon	O
rules	O
and	O
variables	O
defined	O
and	O
fine-tuned	O
by	O
chess	B-Application
masters	O
and	O
computer	O
scientists	O
.	O
</s>
<s>
In	O
contrast	O
,	O
current	O
chess	B-Application
engines	O
such	O
as	O
Leela	B-Application
Chess	I-Application
Zero	I-Application
typically	O
use	O
reinforcement	O
machine	O
learning	O
systems	O
that	O
train	O
a	O
neural	B-Architecture
network	I-Architecture
to	O
play	O
,	O
developing	O
its	O
own	O
internal	O
logic	O
rather	O
than	O
relying	O
upon	O
rules	O
defined	O
by	O
human	O
experts	O
.	O
</s>
<s>
In	O
a	O
November	O
2006	O
match	O
between	O
Deep	B-Application
Fritz	I-Application
and	O
world	O
chess	B-Application
champion	O
Vladimir	O
Kramnik	O
,	O
the	O
program	O
ran	O
on	O
a	O
computer	O
system	O
containing	O
a	O
dual-core	O
Intel	O
Xeon	O
5160	O
CPU	O
,	O
capable	O
of	O
evaluating	O
only	O
8million	O
positions	O
per	O
second	O
,	O
but	O
searching	O
to	O
an	O
average	O
depth	O
of	O
17	O
to	O
18	O
plies	O
(	O
half-moves	O
)	O
in	O
the	O
middlegame	O
thanks	O
to	O
heuristics	B-Algorithm
;	O
it	O
won	O
4	O
–	O
2	O
.	O
</s>
<s>
Deep	B-General_Concept
Blue	I-General_Concept
's	O
evaluation	B-General_Concept
function	I-General_Concept
was	O
initially	O
written	O
in	O
a	O
generalized	O
form	O
,	O
with	O
many	O
to-be-determined	O
parameters	O
(	O
e.g.	O
,	O
how	O
important	O
is	O
a	O
safe	O
king	O
position	O
compared	O
to	O
a	O
space	O
advantage	O
in	O
the	O
center	O
,	O
etc	O
.	O
)	O
.	O
</s>
<s>
The	O
evaluation	B-General_Concept
function	I-General_Concept
was	O
then	O
split	O
into	O
8,000	O
parts	O
,	O
many	O
of	O
them	O
designed	O
for	O
special	O
positions	O
.	O
</s>
<s>
The	O
system	O
combines	O
its	O
searching	O
ability	O
of	O
200	O
million	O
chess	B-Application
positions	O
per	O
second	O
with	O
summary	O
information	O
in	O
the	O
extended	O
book	O
to	O
select	O
opening	O
moves	O
.	O
</s>
<s>
When	O
Kasparov	O
requested	O
that	O
he	O
be	O
allowed	O
to	O
study	O
other	O
games	O
that	O
Deep	B-General_Concept
Blue	I-General_Concept
had	O
played	O
so	O
as	O
to	O
better	O
understand	O
his	O
opponent	O
,	O
IBM	O
refused	O
,	O
leading	O
Kasparov	O
to	O
study	O
many	O
popular	O
PC	O
chess	B-Application
games	O
to	O
familiarize	O
himself	O
with	O
computer	O
gameplay	O
.	O
</s>
<s>
Deep	B-General_Concept
Blue	I-General_Concept
used	O
custom	O
VLSI	O
chips	O
to	O
parallelize	B-Operating_System
the	O
alpha-beta	B-Algorithm
search	I-Algorithm
algorithm	O
,	O
an	O
example	O
of	O
GOFAI	B-General_Concept
(	O
Good	O
Old-Fashioned	O
Artificial	B-Application
Intelligence	I-Application
)	O
.	O
</s>
<s>
The	O
system	O
derived	O
its	O
playing	O
strength	O
mainly	O
from	O
brute	B-Algorithm
force	I-Algorithm
computing	I-Algorithm
power	O
.	O
</s>
<s>
It	O
was	O
a	O
massively	B-Operating_System
parallel	I-Operating_System
IBM	B-Operating_System
RS/6000	I-Operating_System
SP	I-Operating_System
Supercomputer	B-Architecture
with	O
30	O
PowerPC	O
604e	O
processors	O
and	O
480	O
custom	O
600µm	O
CMOS	B-Device
VLSI	O
"	O
chess	B-Application
chips	O
"	O
designed	O
to	O
execute	O
the	O
chess-playing	B-Application
expert	B-Application
system	I-Application
,	O
as	O
well	O
as	O
FPGAs	B-Architecture
intended	O
to	O
allow	O
patching	O
of	O
the	O
VLSIs	O
(	O
which	O
ultimately	O
went	O
unused	O
)	O
all	O
housed	O
in	O
two	O
cabinets	O
.	O
</s>
<s>
Its	O
chess	B-Application
playing	O
program	O
was	O
written	O
in	O
C	B-Language
and	O
ran	O
under	O
the	O
AIX	B-Application
operating	I-Application
system	I-Application
.	O
</s>
<s>
In	O
1997	O
,	O
Deep	B-General_Concept
Blue	I-General_Concept
was	O
upgraded	O
again	O
to	O
become	O
the	O
259th	O
most	O
powerful	O
supercomputer	B-Architecture
according	O
to	O
the	O
TOP500	B-Operating_System
list	O
,	O
achieving	O
11.38	O
GFLOPS	O
on	O
the	O
parallel	B-Application
high	I-Application
performance	I-Application
LINPACK	I-Application
benchmark	O
.	O
</s>
