Jan Liseiwicz

Jan Liseiwicz is a brilliant mathematician, demanding teacher, and formative mentor to Rong Jinzhen, whose talent he recognizes and tries to protect. His later connection to cryptography makes him both an advocate for Jinzhen and a figure of suspicion: accounts first portray him as a codebreaker working against his former student, while Fan Lili’s testimony identifies him instead as PURPLE’s creator and a scientist caught within intelligence work.

Identity and Mathematical Reputation

Born in 1901 into a Polish aristocratic family, Jan Liseiwicz was recognized as exceptional from childhood. His Jewish mother was described as having passed on features that contemporaries associated with Jewish ancestry, while his own intelligence was said to place him almost beyond the scale of the Binet-Simon tests. By four, he was absorbed in competitive games of intellect, including chess; by six, family members and friends were reluctant to play him. The childhood prodigy became one of the most prominent mathematicians of his generation.

At twenty-four, Liseiwicz was named by the Austrian journal Monatshefte für Mathematik as a rising star. The next year he received the Fields Medal, a prize awarded once every four years. His early record included twenty-seven internationally acclaimed papers. This achievement formed the measure against which his later career was repeatedly judged: after moving to China, he produced no further original mathematical papers, except for the work associated with Liseiwicz chess.

Liseiwicz’s reputation also rests on an apparent transformation. Observers described him as becoming a devoted husband and father after going to China, while his original mathematical output ceased. The narrative connects the change to his family life but does not establish that marriage caused the loss of his creative work; Liseiwicz himself, it suggests, might not have known whether his talent had been extinguished by his choices or had simply disappeared. His later teaching and theoretical work complicate any account of him as a genius whose powers had wholly failed.

Teacher, Mentor, and Advocate for Jinzhen

At N University, Liseiwicz taught mathematics for eleven years. His former students included more than half of the university’s small group of internationally recognized scholars. His methods were deliberately unsettling: students had to speak English, could not take notes, and might receive an incomplete or incorrect version of a problem without an immediate correction. He wanted them to test what they heard, think independently, and develop their imagination rather than rely on a polished proof supplied by their teacher. The approach filtered out some students, but it also made his classes a demanding beginning to a mathematical career.

That method became visible when Liseiwicz presented a problem to his class and told the students they need not attend the next session. After the ensuing uproar, he returned to the board and explained that the lesson would instead examine Jinzhen’s solution. He worked through the boy’s answer, then demonstrated three alternative approaches, making the comparison of different routes to a result the substance of the class. He set a further problem for the following meeting, though he considered a correct answer highly improbable. Jinzhen’s work had already exceeded what Liseiwicz expected his students to produce.

Liseiwicz soon concluded that Jinzhen belonged among the greatest students the university had known. He urged Young Lillie to send him abroad, naming Harvard, MIT, Princeton University, and Stanford University as possible destinations. Young Lillie supported the plan but had no money to fund it: family property had been depleted, his savings had gone toward his daughter’s life, and his salary no longer met the cost of living. Liseiwicz pursued the opportunity himself, writing to Dr Gábor Szegő at Stanford. The result was an offer of a funded place for Jinzhen and a money order of $110 for travel. Liseiwicz delivered the news with evident happiness, but Jinzhen became gravely ill just as he was preparing to leave for Stanford. The illness kept him in China, and the planned journey did not take place.

The later account of the scholarship also serves as evidence of Liseiwicz’s regard for his student. Young Lillie’s family had suspected that Liseiwicz might be exploiting Jinzhen for his own research. His effort to send Jinzhen abroad, where the boy could pursue his own future, undercut that suspicion. The narrative presents his attachment as sincere and selfless, while leaving open the possibility that he saw something of his own childhood brilliance in Jinzhen.

Mathematical Chess and the Question of Credit

During a winter when Jinzhen was spending less time at home, he and Liseiwicz were not simply playing chess: they were inventing a new game together. Jinzhen called it mathematical chess. Played on a large board with mahjong tiles rather than chess pieces, it divided the field into two encampments, shaped like a hatch and a Coptic cross, connected by four routes. Each player controlled two routes. The pieces in one encampment began in fixed positions, while the opponent arranged those in the other, intending to create an advantage for their own campaign. Once play began, each player had to redirect the pieces initially placed to the opponent’s advantage and plan how to move them across the board.

The rules made the game a contest against both the opponent and the constraints of one’s own position. Movement changed according to which encampment a piece occupied: pieces in the hatch could neither move diagonally nor jump over others, while both moves were available in the Coptic-cross encampment. Players had to plan routes, manage disadvantageous starting positions, and prepare for the strict conditions under which pieces could enter the opposing camp simultaneously. The game’s design thus demanded calculation not only of an opponent’s intentions but also of how to turn an imposed position to one’s own use.

The game later circulated among mathematicians in Europe and America under the name Liseiwicz chess. Its theoretical importance was compared with von Neumann’s theory of chess as a two-person zero-sum game, though the practical applications of both were described as unproven. Liseiwicz chess was associated particularly with military strategy. For Liseiwicz, whose post-China research was otherwise limited, it became the major achievement of his later mathematical career.

That public recognition came at a cost to Jinzhen. Once the game took Liseiwicz’s name, accounts of its creation gave Liseiwicz the credit and removed Jinzhen from the story, despite their joint work. The narrative calls this unfair while also emphasizing their closeness and Liseiwicz’s efforts to advance the younger man. The tension is not resolved into either simple betrayal or simple generosity: he could support Jinzhen’s future and still benefit from a public account that obscured his student’s contribution.

China, Departure, and the Letter About Cryptography

Liseiwicz had opportunities to leave China, particularly after the Second World War, and Western universities and research institutes sent him invitations. For a time, his actions suggested that he meant to stay. He brought back a large case of books, bought not only the house where he had lived in Sanyuan Lane but its entire courtyard, improved his Chinese, and announced an intention to apply for Chinese citizenship, though the application was never pursued. His attachment to his Chinese family was reinforced by the conditions his father-in-law had imposed when Liseiwicz married his daughter: he was not to take his wife abroad, was not to divorce her, had to learn Chinese, and their children were to bear their mother’s surname.

His decision to leave followed his father-in-law’s arrest, trial, and death sentence for conduct connected to service in the county administration under the puppet government and dealings with the Japanese. At the time, he was awaiting execution. Liseiwicz left after his father-in-law was nearly executed; the account frames the crisis in the context of both the family relationship and the political danger surrounding the man. It does not reduce the decision to a single motive.

After arriving in X Country, Liseiwicz kept in touch with Young Lillie. One early communication was a postcard with a landscape and a return address that disclosed where he lived but not where he worked. In a later letter, he said he worked at a research institute without identifying it. On Christmas Eve, he wrote that Princeton University had combined several independent research groups into an institute for artificial intelligence, and urged that Jinzhen, if recovered, pursue the field. If suitable work could not be done in China, Liseiwicz thought Jinzhen should go somewhere better equipped. His argument continued the earlier effort to secure the boy’s academic future, now focused on artificial intelligence rather than a university scholarship.

Liseiwicz later wrote directly to Jinzhen after meeting Master Rong. He had no way to reach him, so he called back to ask for Jinzhen’s address; after the necessary permission was given, he sent a letter that passed review by both a guard from his side and a Chinese guard. Its premise was a dream in which Jinzhen appeared to be working in a secret unit as a cryptographer. Liseiwicz acknowledged that it might mean nothing, but treated it as an expression of his hopes and fears for his former student. He warned against cryptography, regarding both the creation and decryption of ciphers as destructive to science and intellect. His objections were not merely professional advice: the letter imagined that Jinzhen’s mathematical ability might have drawn the wrong kind of attention and that he could be pushed into secret work.

Cryptography, Conflicting Accounts, and Final Years

The correspondence did not proceed in the straightforward way Liseiwicz might have expected. A reply purportedly from Jinzhen was typed and signed with a forgery; it had been drafted by five experts and approved by three directors to help with the decryption of PURPLE. Its apparent question asked why Jinzhen could not decipher the cipher. Liseiwicz answered quickly, regretting that his dream had proved true and saying that, for Jinzhen’s sake, he felt compelled to disclose a secret he had sworn not to reveal.

The later explanations of that secret conflict. An account within Unit 701 reported that Liseiwicz and the anti-communist Georg Weinacht were the same person. It inferred that he had understood Jinzhen’s ability, anticipated that he might enter cryptography, and tried first to keep him away from the field and then to hinder his decryption of PURPLE. The same account connected Liseiwicz to the exposure of Jinzhen’s success and interpreted his actions as a covert effort to ensnare him. It also records that Unit 701 feared Liseiwicz had warned the creators of BLACK about Jinzhen’s skill, helping them build countermeasures. For Jinzhen, the discovery that his former teacher had become an adversary in this account was a severe personal and professional rupture.

Fan Lili’s testimony contests important parts of that interpretation. She stated that Liseiwicz was not a codebreaker but a cipher creator, and that PURPLE was his creation. In her account, an Israeli representative approached him in 1946 and asked him to devise a cipher for the new state. Liseiwicz produced an initial cipher, became dissatisfied with its flaws, and spent nearly three years developing PURPLE. The cipher proved too difficult for its intended users. Fan Lili further explained that Liseiwicz was brought into the development of BLACK as an observer, not as a direct researcher. Since one person could create only one high-level cipher, his function was to help the researchers avoid making BLACK a simple copy of PURPLE.

Fan Lili also rejected the claim that Liseiwicz was a virulent anti-communist. She described him as a scientist who was politically naïve and therefore vulnerable to being used. In her account, his wish to persuade Jinzhen to remain abroad came from his long-standing interest in artificial intelligence and a hope that they could work together, not from a political plan. She acknowledged the extraordinary circumstance that Jinzhen deciphered both PURPLE and BLACK, one created by Liseiwicz and the other developed with his participation. Because such rapid success could suggest a leak, suspicion fell on Liseiwicz. The testimony presents the suspicion and the circumstances behind it, but does not settle every question of what he knew or intended.

A case file later linked Liseiwicz to high-level military intelligence work for X Country. A note records that he and Fan Lili were placed under house arrest at a military base in the second half of 1970, after BLACK had been broken; they had already been followed and their telephone monitored. Liseiwicz died at the base in 1978. Fan Lili was released in 1981 and went to Hong Kong in 1983 seeking help to return to China; assistance was refused. A later report placed her in her home county, where she was contributing to an engineering project. Liseiwicz’s ending therefore remains bound to the secrecy surrounding his work: the teacher who urged Jinzhen toward open mathematical study became entangled in a world where even his identity, loyalties, and contribution to the ciphers were disputed.