Osaka Natsu No Jin: The Tabletop Battlefield

My wife recently visited for a couple of weeks, during which time we engaged in battle-playing Epoch's simulation　大阪夏の陣 (Osaka Natsu No Jin, or Siege Of Osaka in the Summer). It's a fairly accurate recreation of the Edo period conflict-the order of battle uses the actual forces of both sides, the map is highly detailed (more so than the recent GMT effort), and a playthrough helps to show why the battle unfolded as it did historically. We thought it would be fun to document the game and follow its progress turn by turn, so here it is with our comments on each phase. Randy is playing the tan Western army of Toyotomi Hideyori commanded by Sanada Yukimura, and Ayame is playing the red Eastern army of the Shogunate under Tokugawa Ieyasu (although Tokugawa Hidetada was Shogun and in nominal command). Osaka castle is the enclosed area to the far north with a Western army unit sitting on it. Yukimura's forces are clustered around Tenno-ji temple in the center and the Tokugawa forces are scattered to the south.

Turn 1

Randy: The initial situation is pretty balanced (unlike the actual historical situation). While I have 2 fewer units than the Tokugawa, I get to make the intial strike and I have the advantage of my powerful units being gathered into a potent strike force rather than scattered. I also have Akashi's unit lurking off to the west ready to enter on a future turn. My strategy is to take out as many exposed Tokugawa units on turn 1 as possible before Ayame has a chance to group them for a defence, and hopefully thin them out enough to go after Ieyasu (killing him all but guarantees a win-alternately, I can kill the 3 Tokugawa units under Hidetada's command to the east). Since her ultimate goal is to invade the San-no-maru and take the castle keep, I need to keep a couple of units back there in case she tries to slip a unit past my main force for an easy win-this further weakens my main force, so I need to get good results on turn 1.

Ayame: Randy is an experienced game player so I do not think I will be able to enter into the castle area unless he loses many units early. I will try to sacrifice my front line units in order to acquire time for my remaining force to gather into a strong defensive line. My powerful units such as Date and Maeda are very slow so it is important for the smaller forces to 'die gloriously in battle' and give them time to protect Ieyasu, who I will not risk in battle. I will then try try to eliminate three of his four 'Yukimura' units which will earn me a large amount of 'victory points'. I do not know which of the 4 'Sanada' units is Yukimura. Until Randy decides to reveal them and show the reverse values, I will avoid attacking them.

Turn 2

Randy: My initial assault turned out great-I took down three Tokugawa units (including powerhouse Maeda on my left) without losing any of my own or exposing Yukimura. I was fortunate in that I left my spearhead exposed but Ayame's follow-up response crapped out. I'm setting up an assault down the Western road in conjunction with Akashi's appearance as well, which should pretty much take care of any thoughts Ayame might have of advancing on the castle. With a little luck, I'll be planting my spear in Ieyasu by turn 5.

Ayame: The Gods were not with me this turn. I had hoped not to expose Hidetada's force in battle but it will now be necessary as my counterattacks achieved no result.

Turn 3

Randy: Things didn't go so well this turn. I ran into some bad exchanges which cost me three units and Ayame two. Akashi showed up but since Date has planted himself in the way, I won't risk my western road assault. I did move my unit from the far northwest to the base of the San-no-maru since if things go badly on my left flank Ayame might be able to send Hidetada's force north.

Ayame: Randy's momentum has been stopped. The middle of my line is still weak, but the menace of Hidetada on the right could keep Randy from pressing on. I still do not know where Yukimura is and have not destroyed any of his four units.

Turn 4

Randy: Yikes! A whole lot of killing went on this turn. I lost six units, including one of Yukimura's units (but not Yukimura, who is still hidden). The Tokugawa lost five, including one of Hidetada's command-while killing Ieyasu looks impossible at this point, I might be able to get Hidetada's remaining two units. I now have fewer units at the front line than Ayame, although mine are overall more powerful. However, any rash move here will thin my line to the point where she can slip through to the castle. If this were a real battle I'd fall back, bring up my reserves from the castle, hope she pursued and pick off the vanguard, and then strike for Ieyasu with everything left. But since it's a game and I'm ahead on points, I'll just pull back and avoid battle as much as possible.

Ayame: While Randy's army is now very depleted, his remaining units are mighty and he has wisely managed still to keep Yukimura hidden. I will fall back into a tough line and hope that he does something stupid.

Turn 5-Last Turn


Randy: Stupid? Moi? Not going to happen, since I'm ahead. Ayame still has some tough units in Date and Hidetada. We each lost a unit last turn. I'll fall back some more and expose one unit, which will likely lure Ayame into series of ZOC induced battles that are not to her advantage. She needs to attack and kill off at least two of my units without losing any to win.

Ayame: I will have to assault Randy's position in order to draw or emerge victorious. I will attempt to make a high odds assault against his open unit and then see what happens. If this were real life and there were more turns, I am sure I would be able to take the castle as his forward forces are depleted. But in game terms, I am in trouble.

End Game

Ayame's last assault ended in a simple attacker retreat.
Neither one of us completed the conditions that would have almost guaranteed victory. For Ayame, getting a unit into the Osaka Castle San-no-maru-10 points. Taking the castle keep OR killing three of the four Sanada units, 50 points. For Randy, killing Ieyasu OR all 3 of Hidetada's units-60 points.
Instead, we tally up the victory points for each enemy unit destroyed. Each unit has a different value according to size and the importance of the commander, ranging from 8 for Shogun Hidetada and 6 for Sanada Yukimura to 2 for scrubs like Asano (Ieyasu has no point value since you get an automatic 60 for killing him).
The final tally is-Randy 32, Ayame 26. Although the game doesn't have different levels of victory, I would put this as a Toyotomi marginal victory. In historical terms, Ieyasu would likely just wait for more of his units to reach Osaka and wipe out the Toyotomi next week instead of today.

Final Thoughts

Randy: My initial assault pretty much was the difference here. It took away any possibility of a strong counteroffensive and allowed me to survive the turn 4 bloodbath. Ayame fought well and Ieyasu was never in danger.

Ayame: My losses on turn one proved to be too much to overcome. Losing Maeda was unfortunate as it unhinged my entire right flank. Randy played a careful game after that. He kept Yukimura hidden and did not do anything foolish I could exploit. If we played again, I would make more of an assault on the castle with my forces on the right.

This replay turned out to mirror the historical outcome closely-an overwhelming early assault by the massed Sanada forces against scattered Tokugawa contigents which lost its impetus as the Tokugawa brought up their vast reinforcements. If a couple of more turns had been added, it's possible that the Toyotomi army would have disintegrated as it did in real life. For more on the battle, an easily available source for most Westerners in Japanese is 新歴史群像 #2: 真田幸村と大阪の陣:Shin Rekishi Gunzou #2: Sanada Yukimura & The Siege Of Osaka. In English, try Stephen Turnbull's Osaka 1615: The Last Battle Of The Samurai. It's one of Turnbull's better efforts and an excellent account of both the Winter and Summer campaigns, including all the small battles that ran before the primary engagements.