Siege of Moji

What Happened

In 1561, the castle of Moji (門司城, Moji-jō) came under siege. The fortress belonged to the Mōri clan (毛利氏, Mōri-shi), a powerful warrior house whose capital lay at Yamaguchi. The year fell within the fourth year of the Eiroku era (永禄, Eiroku), a period when rival daimyō (大名, great lords) fought constantly for control of territory and trade.

Moji Castle stood at the northern tip of Kyushu, directly across the narrow strait from the Mōri heartland on Honshu. Whoever held it could choke or open the sea lanes that ran through the strait. The siege was part of a wider struggle over that crossing, and it is counted among the Japanese–Portuguese conflicts — encounters in which Portuguese traders and their ships became entangled in Japanese warfare.

The castle itself is recorded as the object of the conflict, and the fighting is dated to 1561. The outcome turned on control of a single fortified point at one of the most strategically sensitive waterways in Japan.

Background

The Mōri clan had risen through the chaos of the Sengoku period (戦国時代, Sengoku jidai, the "Warring States" era), a century of civil war that ran from the fifteenth into the seventeenth century. By the middle of the sixteenth century the Mōri were the dominant power in western Honshu, ruling from Yamaguchi. Their territory faced the Kanmon Strait, the narrow channel separating Honshu from Kyushu.

Moji Castle sat on the Kyushu side of that channel. For the Mōri, holding it meant controlling the strait and the trade that passed through it. For their rivals on Kyushu, taking it meant breaking Mōri influence on the island and seizing the profits of the crossing.

The 1561 siege belongs to the Muromachi period (室町時代, Muromachi jidai, 1336–1573), the long span of Japanese history named for the Muromachi district of Kyoto where the Ashikaga shoguns had their government. By 1561 that government's authority had largely collapsed, and real power lay with regional lords like the Mōri, who fought one another directly. The siege of Moji was one such direct contest, fought over a castle rather than settled by any central authority.

Portuguese ships had reached Japan in the 1540s, and by the 1560s Portuguese traders were active in western Japan. Their presence fed the competition between clans, because access to foreign trade — and to the firearms the Portuguese brought — could tip the balance between rivals. The siege of Moji is classed among the Japanese–Portuguese conflicts because of this entanglement of European shipping and trade with Japanese warfare.

Why It Mattered

Moji Castle controlled the Kanmon Strait, the passage between Honshu and Kyushu. In an age when sea transport moved goods, troops and silver more efficiently than roads, command of such a channel was worth fighting for. The 1561 siege was a direct attempt to wrest that command from the Mōri.

The siege also illustrates how the Sengoku period actually worked. With the Muromachi shogunate unable to enforce order, power was decided castle by castle, and a single strongpoint could determine which clan dominated a whole region. Moji was exactly that kind of strongpoint.

Its classification among the Japanese–Portuguese conflicts marks a further shift. From the 1540s onward, European traders and their ships became a factor in Japanese politics. A castle siege in 1561 was no longer purely a Japanese affair; control of a strait also meant control of contact with foreign merchants and the goods and weapons they carried.

The Name in Japanese

The Japanese name of the event is 門司城の戦い. It is read in kana as もじじょうのたたかい, and written in romaji as Moji-jō no tatakai.

Broken down character by character:

• 門 — read mo here. The character means "gate". On its own it is also read kado, and in compounds it often appears as mon.
• 司 — read ji here. It means "to administer", "to manage", or "office". Together, 門司 (Moji) is the place name: the district and castle at the strait.
• 城 — read jō here. It means "castle". In this compound it follows 門司 to give 門司城, Moji-jō, "Moji Castle".
• の — read no. This is the possessive and linking particle, written in hiragana rather than kanji. It joins "Moji Castle" to "battle", giving "the battle of Moji Castle".
• 戦 — read tata in this word. It means "war" or "battle". On its own the character is also read sen, as in 戦争 (sensō, war).
• い — read i. Hiragana, completing the verb-derived noun 戦い (tatakai), "a battle" or "a fight".

So the whole name parses as 門司 (Moji, the place) + 城 (castle) + の (of) + 戦い (battle): "the battle of Moji Castle". Note that Japanese castle names are formed by adding 城 to a place name, so 門司城 is simply "Moji Castle", not a separate word for the fortress.

Key Figures

The Mōri clan (毛利氏, Mōri-shi) held Moji Castle in 1561. The clan's capital was the city of Yamaguchi, from which it dominated western Honshu and projected power across the strait into Kyushu. The defence of Moji was a Mōri interest, and the castle's loss or survival bore directly on the clan's grip on the crossing.

The attackers were the Mōri's rivals for control of northern Kyushu, the clan whose bid for the castle produced the siege. Portuguese traders and shipping were present in Japanese waters in this period and are bound up with the event, which is classed among the Japanese–Portuguese conflicts.