INTERACTIVE BATTLE
Osaka Winter Campaign
November–December 1614 (Keichō 19) · Osaka Castle, Settsu Province
Triggered by the Hōkōji bell inscription incident, Tokugawa Ieyasu ordered the daimyo to take the field, and the Tokugawa forces—said to number around 200,000—besieged Osaka Castle. The outer rampart and Sanadamaru, built by Sanada Nobushige, repelled the Tokugawa assault, but a truce was reached on December 19, and the outer moat and rampart were filled in before the summer campaign the following year.
Background
Even after the Battle of Sekigahara in 1600, Toyotomi Hideyori and Yodo-dono retained Osaka Castle and the former Toyotomi domains, while the Tokugawa family advanced their hereditary hold on the shogunate and realigned daimyo domains. In 1614 (Keichō 19), negotiations by Katsugi Katamoto broke down over the interpretation of the bell inscription at the Hōkōji temple rebuilt by Hideyori, which read 'Kokka ankō' and 'Kunshin buyaku,' prompting Ieyasu to order the daimyo to march on Osaka from September through October.
Outcome
The Tokugawa forces surrounded Osaka Castle in mid-November but were repelled in an assault on Sanadamaru, defended by Sanada Nobushige, on December 4. A truce was concluded on December 19, during which the Ninomaru and Sannomaru were demolished and the outer moat and rampart were filled in, severely weakening Osaka Castle's defenses.
Course of the battle
1 Mid-November
Siege of Osaka Castle
2 December 4
Battle of Sanadamaru
The Tokugawa attacked Sanadamaru, an outer rampart and fortified outpost south of Osaka Castle built by Sanada Nobushige (Yukimura), but Nobushige repelled the assault.
Points of debate
Specific Tokugawa units that attacked Sanadamaru (such as Maeda Toshitsune, Ii Naotaka, and Matsudaira Tadanao) are mentioned in commercial history websites, but official sources from public institutions, museums, and local authorities consulted for this research do not specify unit names, so this remains unconfirmed.
Sanada Nobushige — builds and defends Sanada-maru, repels Tokugawa forces
Sources234·Certainty: High
3 December 19
Truce Concluded
Negotiations between the Tokugawa and Toyotomi forces resulted in a truce, ending the Osaka Winter Campaign.
Sources26·Certainty: High
4 Between the Winter Campaign and Summer Campaign
Filling of the Outer Moat and Rampart
In accordance with the truce, the Ninomaru and Sannomaru of Osaka Castle were demolished and the outer moat and rampart were filled in. Excavations confirmed that the moat was backfilled rapidly in a short period, and human remains bearing sword wounds were found among the fill.
Points of debate
The party responsible for the filling—whether the Toyotomi filled the Ninomaru and inner moat while the Tokugawa filled the Sannomaru and outer moat—is discussed in expert articles, but this research could not confirm it from primary sources held by public institutions, museums, or local authorities, so it is treated as a matter of debate.
Sources56·Certainty: High
Historical significance
Deprived of its moat, Osaka Castle became difficult to defend through siege, making it a factor in the Toyotomi decision to fight a pitched battle outside the castle in the Osaka Summer Campaign the following year.
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Key figures
徳川方
2
豊臣氏
1
Defender of Demaru and Sanada-maru
Built Sanada-maru and repelled Tokugawa attacks
Sources24·Certainty: High
Other events of 1614
Notes on the data
The precise extent and shape of Sanadamaru remain unconfirmed even after excavations in 2016; the location on the map is a proposed site near Meshiya-chō, Tennōji Ward, and the Osaka Myōjō Academy. The party responsible for filling in the moat—whether the Toyotomi filled in the Ninomaru and inner moat while the Tokugawa filled in the Sannomaru and outer moat, or another arrangement—is debated, and the main text does not specify.
Sources consulted
- 国立公文書館「方広寺鐘銘事件」
- 国立公文書館「大坂冬の陣・夏の陣」
- 大阪歴史博物館「大坂の陣 激戦地を歩く」
- 大阪市天王寺区「大坂の陣最大の激戦地 真田幸村と真田丸」
- 大阪城天守閣「大手前で見つかった豊臣時代の堀」
- 城郭マスタ（shiro.geojson）
The numbers in the text refer to the list above. Certainty indicates how far a statement is supported by the cited sources; it does not refer to the precision of the coordinates or the dating.
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