The invasion had arrived the evening before. On May 23, 1592, Konishi Yukinaga's (小西行長, Konishi Yukinaga) fleet of approximately 400 transports had sailed from Tsushima Island (対馬, Tsushima) and appeared in Busan harbor by nightfall, carrying 18,700 men in the full embarkation force. Korean lookouts had seen them coming. There had been no time to do anything useful about it.

Jeong Bal (鄭撥, Jeong Bal) was 39 years old and the commander of Busanjin (釜山鎮, Busanjin), the main fortress guarding the port. He had reportedly spotted the fleet the previous evening while hunting on Yeong Island (影島, Yeong-do), just off Busan harbor — the fall of Busan literally beginning with a man looking up from a hunting trip and watching history arrive on the horizon. He returned immediately to the fortress and prepared what defense was possible.

Before the assault on Busanjin began, a final diplomatic move was attempted. So Yoshitoshi (宗義智, So Yoshitoshi), the 24-year-old daimyo of Tsushima, sent a messenger to Jeong Bal with an offer: stand aside and allow the Japanese forces to pass through Korea unopposed, and no harm would come to the garrison or the city. So Yoshitoshi's position was extraordinary. The So clan had managed the trade relationship between Japan and Korea for generations — they were the intermediaries, the go-betweens, the people who kept commerce and diplomacy flowing across the Korea Strait. So Yoshitoshi was married to Toyotomi Hideyoshi's (豊臣秀吉, Toyotomi Hideyoshi) adopted daughter. He had spent years attempting to broker a peaceful settlement, traveling between both courts. His letters suggest deep personal ambivalence about the invasion he was now helping to lead. And here he was, offering the man across the wall a chance to live.

Jeong Bal's reported answer was precise in its military logic: he had received no orders from Seoul authorizing him to stand down or grant passage. Without such orders, it was not within his authority to make that decision. His duty was to defend his post. He would not surrender on his own initiative, even to save his garrison, even to save himself. The offer was refused.

The assault began. Japanese forces moved to seize the high ground of the mountain behind the fortress — the commanding ridge that overlooked Busanjin's northern defenses. From those heights, arquebus (火縄銃, hinawaju) fire rained down into the fort. The arquebus had been introduced to Japan by Portuguese traders in 1543, forty-nine years before this battle, and Japanese gunners were among the most experienced in the world after decades of civil war in which the weapon had become decisive. Korean defenders were skilled archers — the composite bow was a formidable weapon in open field conditions — but firing uphill against firearms from below a ridge was a losing position. The arrows ran out. The Japanese fire did not.

At approximately 9 o'clock in the morning on May 24, 1592, Jeong Bal was struck by an arquebus bullet and killed. He was the first high-ranking Korean officer to die in the Japanese invasions. His death caused morale to collapse. The fortress fell shortly after.

Japanese records claim Korean casualties of approximately 8,500 killed and 200 captured — figures drawn from the attackers' own accounts and likely inflated. The same records list Japanese losses as 1 killed and 3 wounded, a figure historians consider an almost certain undercount, but the lopsided nature of the engagement is not disputed. The fortress had held for less than a morning.

With Busan in Japanese hands, the port became the primary landing point for the entire invasion force. Kato Kiyomasa (加藤清正, Kato Kiyomasa) with the Second Division and subsequent waves came ashore in the days that followed. On May 25, Japanese forces moved on Dongnae Fortress (東萊城, Dongnae-jo), whose commander Song Sanghyun (宋象賢, Song Sanghyun) also refused to surrender and was killed in a twelve-hour siege. The pattern of the invasion's opening was set: Korean commanders chose honor over survival, and fell one by one. Seoul fell on June 12, 1592 — nineteen days after the fleet appeared in Busan harbor.

The man who had extended the last offer of mercy — So Yoshitoshi — went on to lead forces deeper into Korea, fighting in a war he had spent years trying to prevent. The world his family had built across the Korea Strait was gone. He outlived the invasion, but the trade network and diplomatic relationships the So clan had maintained for generations did not recover in his lifetime.

Today, a statue of Jeong Bal stands near the Japanese Consulate in Busan, facing the sea. The city he could not defend is now one of the largest ports in the world. The fortress where he died is a reconstructed historical site. Both nations remember the morning differently, but both remember it.