Make use of every second and every inch

“Make use of every second and every inch” is a maxim of vigilance and opportunity in Rong Jinzhen’s account of a stolen briefcase, and a concise description of cryptographic work. Its force comes from joining two scales of attention: a thief’s use of a brief interval and a codebreaker’s long patience for a single opening.

The Maxim in the Theft

After Rong Jinzhen describes his missing case, a professor recalls seeing a young man in military plain clothes on the train’s connecting platform about an hour earlier. The man had been leaning against a door-frame and smoking, with an attaché case like Rong Jinzhen’s in his hand. The professor had taken little notice of him; when he returned from the bathroom, the young man was gone.

Rong Jinzhen concludes that the man had likely stolen his case. What looked like idle waiting, he reasons, was the selection of a target: the professor’s trip to the bathroom gave the stranger his chance. The maxim names the economy of that brief opportunity. Rong Jinzhen’s bitter laugh follows his recognition that the apparent stillness had concealed deliberate attention and action.

A Principle of Cryptography

In an interview transcript, Director Zheng states that cryptography likewise requires making good use of every second and every inch. The surrounding explanation turns the maxim into a method of close observation. A cipher may seem like an immense, seamless net, but its use can produce slips; those small failures create openings through which a sharp mind may enter its structure.

The imagery makes the work depend not on force but on noticing what breaks the apparent whole. A slip becomes a trace, and a trace may offer access to the cipher’s inner passages. The maxim therefore links the patient search for weakness in a code to the thief’s alertness to a lapse in another person’s attention, without making their aims or actions equivalent.

Patience and Its Limit

Rong Jinzhen has spent years waiting for such openings in BLACK, enduring countless days and nights without deciphering it. The contrast complicates the maxim: attentiveness and patience are necessary, but they do not ensure success. The phrase first explains how a brief opportunity could be exploited; in the cryptographic account, the same discipline persists without a solved cipher. Its recurrence places practical vigilance beside the harder problem of waiting for a gap that may not appear.