Not to be indelicate, but there are some things we just can’t control. After all, when you’ve got to go, you’ve got to go. While it is true that some of us are blessed with bigger bladders and greater stamina when it comes to holding it in, there isn’t a single person on the planet who doesn’t know what it is to reach the point where you simply need to relieve yourself.

For that reason, we shouldn’t be too hard on Shimura Kikujiro. He did the best he could, but he knew if he waited any longer to empty his bladder, it would be a catastrophe. Little did he suspect that his impromptu bathroom break would be the direct cause of something far worse than some damp drawers.

Before we get to Kikujiro and his fate-filled near-bursting bladder, we need a quick primer on the foreign relations between Japan and China. In 1894, the First Sino-Japanese War began with Japan’s invasion of China. It ended the next year, resulting in China losing a significant portion of its territory. This weakened China’s prestige and power, encouraged Japan’s territorial ambitions, and tempted other nations to take a bite out of China’s holdings. A decade later, Russia and Japan found themselves at odds over the Manchukuo region of China. This culminated in the Russo-Japanese War of 1904-1905. To the surprise of nearly everyone except the Japanese, Japan won the war. Consequently, Japan was given a lease over the contested area.

As Japan gained strength and confidence, China broke into competing factions. Its lack of strong, national unity further encouraged the territorial ambitions of its neighbors.

Japan, hoping to expand its territory and influence, grew impatient and staged a sabotage of its own South Manchuria Railway on September 18, 1931. They tried to blow it up near Mukden (today’s Shenyang). The operation did not go off as planned and caused so little damage that trains were using the rails within minutes of the explosions.

The primary purpose of the operation, however, was not to destroy the railway but to cause an international incident. The Japanese accused China of sabotage. Claiming that they needed to protect their national interests, the Japanese expanded their occupation and consolidated adjacent occupied territories, creating the puppet state of Manchukuo.

Japan’s attempt to place the blame on China was seen for the naked power grab that it was. The League of Nations booted Japan from its membership. Given that the League of Nations had less influence and authority than an elementary school hall monitor, this did little to cool the imperial government’s expansionist policies.

Japan’s actions did, however, send a shockwave through China. Faced with a dangerous adversary, the competing Chinese factions agreed to temporarily put aside their differences. In 1936, the Communist Party of China (CPC) made peace with the Kuomintang (KMT), forming the United Front.

By 1937, Japanese troops were in Fengtai, a district to the southwest of Beijing. The district was filled with walled cities, intended to fortify Beijing from attacks coming from that direction. One of these cities, Wanping, was adjacent to Beijing, connected to the capital city by the Marco Polo Bridge.

The Japanese took advantage of their proximity to Beijing by conducting military exercises in Wanping. The maneuvers were designed to keep the Chinese military and civilians on edge and demoralized. Additionally, Japan was always on the lookout for anything that could be used as a pretext for further territorial expansion.

This brings us to July 7, 1937, and our previously-mentioned Shimura Kikujiro and his history-changing bladder. Kikujiro was a private in the Japanese Imperial Army. He and his fellow soldiers were engaged in training exercises near the Marco Polo Bridge at 11:00 that fateful night.

Japan had promised China that it would give advance warning about its training exercises, but it had no intention of keeping that promise. The maneuvers on July 7 were unannounced.

So was Kikujiro’s need for a bathroom break. The pressure in his bladder grew in direct proportion to the anxiety felt by Chinese soldiers and civilians on the other side of the bridge. He tried to ignore it for a while. Then he tried to suppress it. He quickly discovered that his efforts to subdue his bladder were proving to be as fruitless as the Chinese attempts to control its invading neighbor.

Finally, unable to resist the call of nature any longer, Kikujiro stepped away from his comrades to take care of business. Finding appropriate facilities was out of the question; the city had only recently gained electrical service. Public toilets were out of the question.

Kikujiro made his way through the streets to find a place with sufficient privacy to relieve himself. Mission accomplished and feeling much relieved, he made his way back to rejoin his unit. Much to his surprise, his fellow soldiers were not there. They had returned to their camp. Since Kikujiro was not in the habit of making a public announcement concerning his bodily functions, no one knew he had left.

It wasn’t until the unit reassembled at the camp and took roll that Kikujiro’s absence was noticed. The officers immediately dispatched some men to Wanping, demanding entry to search for their missing man.

It must be remembered that Wanping was a walled city. The city leaders closed the gates when the Japanese soldiers left, and they were reluctant to reopen them for Japanese soldiers at that late hour. The Chinese offered a compromise. They would conduct a search of the city themselves and report their findings to the Japanese.

The Japanese were indignant. It was their man who was missing, so they insisted that they had the right to conduct the search themselves. If the Chinese would not allow them to do so, they would force their way in and take matters into their own hands.

The Chinese would not budge.

Shortly after midnight, a small Japanese unit attempted to climb the city walls to make good on their threat. The attempted breach was discovered and successfully fought off. In response, the Japanese issued an ultimatum: open the gates and permit a proper search or be attacked.

The Chinese attempted to negotiate a peaceful settlement, but it was too late. At 4:50 a.m., July 8, 1937, the Second Sino-Japanese War began. It became the excuse Japan was looking for to justify a full-scale invasion of China. It became the largest Asian war of the twentieth century, ending only with the surrender of Japan in September 1945 at the end of World War II.

Before the last shot was fired, the war would claim the lives of 3.22 million Chinese soldiers, 9.13 million civilians who were killed in crossfire, and another 8.4 million non-military casualties. Japan recorded between 1.1 million and 1.9 million military casualties.

There is one more piece to this puzzle that would not be publicly disclosed until nearly 80 years later. In 2013, Japan’s National Diet Library unsealed its files relating to the Marco Polo Bridge Incident. The records disclosed that before Japanese troops began their assault on Wanping, Private Shimura Kikujiro finally found his way back to his camp. Shame-faced and apologetic about getting lost, he explained that he had simply gone for a bathroom break and that the Chinese had nothing to do with his absence.

For that reason, it would be unfair to place all the blame on Kikujiro’s bladder for the carnage that followed. Clearly, his urinary excursion was just the excuse his leaders had been looking for.

Even so, perhaps it would be good to heed the advice given by fathers before every family trip: if you have to use the bathroom, do it now; it won’t be convenient for anyone if you wait until you can’t hold it any longer.