Ikeda Toshio was one of the main figures in the development of Japan's
computer industry. He was also a keen amateur go player. He brought a
computer engineer's logical analysis to the game itself, and to the
question of its rules.
Ikeda was born in 1923 into an artistic family. His father and older
sister were both painters. Ikeda's own interests were directed more
toward music and mathematics, especially geometry. He taught himself
higher mathematics in his early teens, won prizes in competitions, and
devised original proofs of the Pythagorean theorem.
In 1946 Ikeda graduated from the Tokyo Institute of Technology and went
to work for Fujitsu, Ltd. At that time Fujitsu's main business was
manufacturing telephone equipment for the Ministry of Communications.
Fujitsu's telephone sets did not always work perfectly, and at one point
an order went out from General Headquarters (Japan was under American
occupation) that Fujitsu was to cease production. Ikeda turned his
talents toward finding the cause of the problem. This led to his first
published paper, a thorough mathematical analysis of the rotary motion
of a telephone dial.
Although the cease-production order was rescinded, this was a time
of serious inflation in Japan and GHQ instituted stiff deflationary
measures. One measure curbed expansion of the telephone network,
and Fujitsu had to lay off a third of its work force. Seeking means
of corporate survival, in 1952 Fujitsu's management decided to look
into the new field of computers. In the course of experiments for his
telephone-dial analysis Ikeda had built an electronic pulse counter, so
it was natural for him to join the computer project.
Fujitsu's first computer, a relay-operated machine targeted at the Tokyo
Stock Exchange, was designed and built in six months by a small team
of engineers. Ikeda's performance on the team was sometimes erratic.
He worked intensely on the design but forgot all about producing
his assigned schematic diagrams. He was caught up in the theory of
arithmetic and logic circuits, filling notebooks with this idea and
that. During the test phase, when the team worked around the clock for
two weeks, Ikeda kept it awake through cold nights by singing Schubert's
"Winterreise" at the top of his lungs in German.
The completed computer had a balky temperament and caused its creators
much anxiety. It worked when shown to the stock exchange officials, then
broke down as soon as they left. The stock exchange rejected it in favor
of a UNIVAC punched card system. Ikeda, however, had become irresistably
fascinated by computers. A few months later he started designing the
FACOM 100, a larger relay computer suitable for scientific computations.
Ikeda now proved to be a first-rate computer designer, but his working
hours grew increasingly irregular. He had low blood pressure and was not
at his best in the morning, so he would often toil through the night
to the point of exhaustion, sleep during the day, then wake up in the
evening and start in again. This was not the normal Fujitsu schedule,
so Ikeda frequently worked at home. Fortunately, he had superiors who
recognized his ability and tolerated his behavior.
Although only one FACOM 100 was ever built, it was followed by more
advanced relay computers and peripherals and Ikeda continued to display
his talents. An engineer was having trouble designing a linkage system
to move the type bars of a line printer. Ikeda analyzed the problem,
found a mathematical solution, and wrote a program for the FACOM 100
that quickly calculated the answer. This was Fujitsu's first experience
with computer-aided design.
In the late 1950s Fujitsu began making vacuum-tube and parametron
computers, followed in the 1960s by transistorized models. In his 1962
New Year address, Fujitsu's president declared that Fujitsu would stake
its corporate destiny on computers. In 1968 the first FACOM 230-60
was installed at the University of Kyoto. This was a revolutionary
machine with all integrated-circuit logic that supported multitasking
and multiprocessor configurations. A best-seller, in 1970 it pushed
Fujitsu into first place in market share among Japan's domestic computer
During this time Ikeda was promoted to positions of increasing
responsibility, first in computer hardware then in software development.
He is remembered not only for his engineering genius but also for his
inspiring leadership qualities. Some idea of Ikeda's contributions can
be gained from the list of awards he received:
in 1958, a Kanto Regional Invention Award for an "interconnection method
for assuring the safety of electrical computer circuits;"
in 1958, a Mainichi Industrial Technology Award for a "relay-type
in 1966, a National Invention Award for a "method of address
modification in the address modification unit of an electrical
in 1966, an Ohm Award for "development of the FACOM 230-10
very-small-scale electronic computer;"
in 1970, a Merit Award from the Director General of the Science and
Technology Agency for "development of the FACOM 230-60 large-scale
electronic computer system;"
in 1970, an Imperial Invention Prize for an "interrupt system using an
Ikeda's reputation as an engineer was matched by his reputation as an
eccentric. He was the type of person who might be late to work because
he had decided to listen to a Beethoven recording; who entertained
dinner parties with juggling and balancing acts; who wrote about
computers programmed to fall in love with each other and marry; and who,
when scheduled to attend an important executive meeting, was once found
at home instead, seated half-clad on a window ledge, carving a toy out
In 1968 a Fujitsu official arranged for Ikeda to meet Gene Amdahl. Ikeda
had great confidence and pride in his engineering skills, but in the
architect of System/360 he recognized an equal. After Amdahl set up
his own company in 1970 the two men were able to associate more freely
and soon became, in Amdahl's words, "fast friends." The relationship
developed into more than just friendship. Ikeda had long wanted Fujitsu
to establish an engineering center in the United States. In 1971 this
dream materialized on the grounds of Amdahl Corporation in Sunnyvale,
California. Next year Ikeda was able to persuade Fujitsu to invest
financially in the new American company.
In 1973 Amdahl Corporation experienced growing pains, and Ikeda strove
to tide them over. He shuttled by plane between Tokyo, where he
convinced skeptical Fujitsu executives that the partnership with Amdahl
was worth continuing; San Francisco, where he advised Amdahl on matters
ranging from company management to hardware debugging and fought off
suspicions that Fujitsu was attempting a take-over; and Chicago and New
York where he lined up further support for the fledgling corporation.
International in his outlook, during this time Ikeda worked on joint
projects in Spain and Canada as well. Then in November 1974 he suddenly
collapsed while waiting to meet Canadian representatives at Tokyo's
Haneda Airport. He died four days later of cerebral hemorrhage, without
regaining consciousness. He was fifty-one years old.
Though he did not live to see the results, the efforts Ikeda made in
the last year of his life turned out successfully. In December 1974
the first Amdahl 470V/6 crossed the Pacific, designed and developed
in California, manufactured at Fujitsu plants in Kawasaki and Nagano,
destined for installation at NASA. Other top-level mainframe users
likewise began replacing their CPUs with the 470V/6, and Amdahl started
marketing Fujitsu's new M Series of processors in the United States.
This was what Ikeda had planned.
From childhood on, Ikeda enjoyed both intellectual and physical games.
In high school he was a star center who led his basketball team to a
hundred consecutive victories. This was also when he started playing
go; he would stay up late at night after basketball practice to tackle
the school Meijin. When Ikeda entered Fujitsu he played at the four-kyu
level, but he was already keen enough to spend half his first month's
salary on a magnetic go set. (That left him without enough money to eat
meals; to fend off starvation he had to sell most of his books to a
second-hand book shop.)
When back problems put an end to his basketball career, Ikeda's passion
for go redoubled. He clipped the go columns from newspapers and amassed
a huge collection of professional games, many of which he knew by heart.
From 1950 to 1956 he and two other Fujitsu engineers took weekly lessons
from a 2-dan professional. Always one to seek the strongest opponents,
Ikeda later founded Seihokai, a group that met weekly with Go
Seigen and Rin Kaiho. Awhile before his death Ikeda managed to win one
game apiece from these two at a three-stone handicap.
When the Fujitsu group began planning its exhibit for the 1970
Exposition in Osaka, Ikeda was among the planners. The theme was
"Computopia," a futuristic vision of the interplay between computer
and man. Some of the interplay was to take place on the go board.
Ikeda began looking for a set of rules logical enough to satisfy
the requirements of computer go and, more importantly, the future
international go-playing community.
Ikeda attacked the rules problem with the same intensity he had shown
in attacking the rotary motion of the telephone dial and the design of
computers. He filled notebooks with handwritten rule analyses, lists of
principles, diagrams, comparison charts, and drafts of new proposals. He
published his conclusions in a series of eleven articles that appeared
between September 1968 and November 1969 in Igo Shincho.
In the course of these articles Ikeda revised his rules proposals
several times. The final version, given in Part I of this book, consists
of overlapping rulesets that share the same basic definitions and rules
of play, but differ in how they end and score the game. Ikeda proposed
three sets of Chinese-style area rules and two sets of Japanese-style
territory rules. For completeness I have added a third set of territory
The articles themselves form Part II. They are presented as they
appeared in Igo Shincho with only minor editing, such as the
insertion of a few parenthetical remarks and correction of mistakes in
the diagrams. Some of Ikeda's comments about the Japanese rules are now
out of date; updates are given in footnotes.
Ikeda's efforts at rule reform were largely ignored during his lifetime,
but he would probably be glad to know that in 1978 the New Zealand Go
Society switched to rules similar to his area rules II (differing mainly
in allowing self-capture), and in 1991 the American Go Association
formally adopted rules embracing both area rules II and territory rules
Three people have been most helpful in the preparation of this book.
Okamoto Akira of Fujitsu Business Systems Ltd., who was closely
associated with Ikeda as a computer engineer and a go player, provided
the foregoing information about Ikeda's career. Fujisawa Yoshihiro
of Fujitsu's Advertising Division made the publication arrangements.
Okasaki Masahiro introduced me to Ikeda's work and provided copies of
his articles and notes, as well as much other information and advice.
I am grateful to all three, and to Miyamoto Naoki (9 dan) of the
Kansai Kiin who gave permission to publish the material from Igo
Japanese names are given in the Japanese order, family name