Thursday, May 7, 2026

Nobunaga's Ambition: BASIC bushido

Rolling a super-Nobunaga.

For this last post, I'm going to try to tackle the hardest difficulty of Nobunaga's Ambition, but I won't play fair. I have save states. I have the source code. And I'm going to do my best to explain how things work. And oh, boy, is it kind of insane!

First of all, let's look at the stats. Everyone's got them, but on anything but the lowest difficulty, pretty much everyone gets better stats than you, especially Tokugawa. So I am savescumming to ensure I get something decent.

I have an IQ of 108 (this might not sound amazing but my last Nobunaga was basically an inbred imbecile), constitution of 98, ambition of 110, charisma of 100, and luck of 93. What does it all mean?

Not much! These stats, as it turns out, are simple combat modifiers, and there is zero distinction between the first four. I'll get into the specifics later, but at a glance, just average them, compare them to the average of the other guy, and that shows you how much of an advantage/disadvantage you are, all other things being equal. Tokugawa, at the highest difficulty, easily has an average of 140 across these stats, so I would need 140% the number of troops in order to match his power. Either that or beat him in other stats.

Luck applies a small combat bonus which does not scale with your army size/morale/training. It's basically inconsequential unless you're very evenly matched otherwise. Even then it's probably inconsequential because combat rolls are a factor, and those do scale with your other stats.

One other factor here is that constitution increases in the spring, but decreases during random plagues. Apart from that, your stats are set.

 

1560 


A plague has hit. Every spring, there is a 30% chance of typhoons, and a 7% chance of plagues (but no chance of both). Either event affects the region as a whole, but not every province; in the event of a plague, each province has a 25% chance of being affected, and mine was. This reduces your rice production to 40%-90% of its previous value, and your army size by the same value.

Not a great start, but I have math on my side.

You need rice to feed your army, and the formula for the autumn rice harvest is deterministic:
[Production] * [Flood control]/100 * [Peasant loyalty]/100 * [Peasant wealth]/100 * [Tax rate]/100

 

This maximizes at 1000. Not important right now, but it will be! 

My values right now are the cyan numbers - 24, 45, 49, and 67. At a base tax rate of 50, I'd get one lousy koku this autumn, and I'm going to need nine to sustain the army as it is, let alone grow it!

At first glance, you might think the best way to get these numbers up is to increase the lowest stat, which is production. This is wrong for a simple reason; production is by far the most expensive stat to raise! One gold raises it one point, while flood control goes up by five points per piece, and also has the benefit of mitigating typhoon damage.

Even better than that, gifts to your people increase both loyalty and wealth by 100/[Production] per coin/koku, or 4.2 each.

But if you really want to get those numbers up, you gotta do it the same way as the 1%. Abuse the tax code!

Taxes adjust loyalty and wealth by this formula:
50 - [new tax rate]
 

See how this might be abused? It's not diffing the old rate and the new. It's diffing the old rate and the baseline of 50! Set it to the minimum of 1, and you increase both numbers by 49. You can do that repeatedly. Then you can set it right back without affecting them at all!

So that's what I do. In the spring, I lower the tax rate to 1, and in summer, I raise it right back to 50 in time for the harvest, which produces 6 koku rather than the 5 I'd get from gifting my gold. But that's just the beginning. Over the next three seasons, I set the tax rate to 1 three times, which does nothing but make the peasants happier and richer, and in the summer, just before harvest, I set it to 100 which makes them a little sadder and poorer. This gives me a harvest of 45 koku, a decent surplus of 36.


1561


I'm still lagging behind Tokugawa, and at this point investing in flood control would be more valuable than tax abuse. So I do both. Provincial wars start to heat up, but I'm left alone for now. The harvest next autumn is 263 koku, which way outpaces Tokugawa, though his wealth and martial growth is starting to be worrisome.


1562


I'm rice rich, but gold poor. Too bad the merchant isn't here right now. I spent what little I have on troops, train a bit, and Kitabatake attacks with a slightly superior force. 

I said I'd explain how combat works, and a roughly even battle is the most interesting one, so this is the ideal place for it.

The single most important stat here is each unit's strength, a number at the bottom of the hex. These are distributed in proportion to the overall army size, always in multiples of ten, and priority given to the highest rank. My army size is 12, so my hex strengths are 30+30+20+20+20. His is 13, so they are 30+30+30+20+20.

Combat strength is determined by this formula:
[Unit strength] * ([Stat bonus] + [terrain bonus]) * [Random factor] * [Lord bonus] + [Luck bonus]


The stat bonus is the sum of seven stats, divided by 700. IQ, constitution, ambition, charisma, army loyalty, army training, and weapons. His bonus will be 1.21, mine will be 0.98.

The terrain bonus applies a flat bonus from 0-2 based on the terrain the unit is in. 0 for plains, 1 for forests, 1.5 for forts, and 2 for castles. As my strongest units are in a castle and fort, respectively, I'm actually in a pretty good position. And I believe the bonus applies even if you are attacking from a fortified position.

The random factor is a multiplier from 0.6 to 1.6.

The lord bonus is a flat multiplier of 2 if the clan lord is personally leading the fight. 1 otherwise. When you attack, you can decide to have Nobunaga lead or not, but if your #1 unit is lost, then it's game over. When you are attacked, this depends on whether the province attacked is where Nobunaga currently is or not.

Finally, the luck bonus is your luck stat divided by 50.

 

So, let's look at my #1 unit vs. the #4 intruder outside his gate. My combat strength would be:
30 * 2.98 * [Random factor] * 2 + 1.86 = 109-288


His would be:
20 * 1.21 * [Random factor] * 2 + 1.86 = 31-79
 

Whoever's is higher does damage, unless the difference is less than 10. Mine is guaranteed to be bigger, so I will do damage, and this will simply be the difference divided by 10.

An average random factor would mean 13 points. This is exactly how much damage I do.


 

So, this is really my #1 and #2 units' fight, and the best thing they can do is not move from their fortifications. #3 and #5 are stuck on the left side and won't be able to do much but finish off wounded units. #4 is stuck on the right side with all of Kitabatake's stronger units and won't be able to hurt them much even from the advantage of cover in the woods.

I take a few losses but I win and take his province. Unfortunately, Saito immediately invades and takes it from me. But then he immediately invades Owari and loses! Both provinces are mine! But then Tsutsui invades Iseshima, which I cannot possibly defend, and forces me to retreat.

 

1563

 

After that tumultuous winter, I'm still alive, but the weakest clan on the map. Gotta arm in a hurry! Good news, though - the merchants are here, and I have over 300 koku stocked in Owari. And prices are decent! I sell it all, and with the cash, hire 234 soldiers; just enough that I will have money left to pay them - the harvest will bring enough to feed them. From Mino #9, I transport the entirety of its wealth back to Owari; I cannot defend two provinces at this time. Sure enough, Mino is attacked and taken this season by the Tsutsui clan. But the rice arrives in Owari, which I sell and use to cultivate the land, maxing out the rice harvest.

The remaining money, and I will definitely want more of it, goes into the town itself. The formula here is simple; each coin you invest in the town improves the town value by one point. And each autumn you collect cash revenue equal to your town's value multiplied by a random value between 0.5 and 1.5. It's a fast return on your investment, but that doesn't do you much good if you get invaded before you can spend it. But if I put in my entire savings of 523, the worst I can collect from that is 261, which will still pay the soldiers.

 

1564

 

Oh, boy. Miyoshi and Asakura are quickly unifying! And I'm looking like I might be Miyoshi's next territory. But Owari is an economic powerhouse that just withstood a plague and collected 422 ryo and produced 868 koku in one year. Imagine what I could do in another!

I'm not going to invade anyone yet, though - I don't feel confident enough I could conquer a province and then defend it and Owari.

I invest in more flood control, sell the excess rice when the merchants come, and dump the gold right back into the town - all 1646 of it. The rest of the year is peaceful.

 

1565 


 

It's time to start thinking about invasions. Tempting as it might be to eliminate Tokugawa, any force I might send his way either leaves Owari inadequately defended from Miyoshi, or is itself inadequately large to defend itself from, well, everyone. Besides, my army could stand some improvement before I go all-in. I buy weapons; 9000 points worth of them (which is all I am allowed), give all of my rice to the army for a nice loyalty boost, and spend the rest of my cash on more soldiers.

Only then do I invade, and I target Mino #9 to the north, bringing 247 well-armed soldiers to engage the 109 stationed there. And the fight is over before I can even issue an order.

 

1566



Well, crap. I expected Mino to fall easily, but I didn't expect this would get me the whole Miyoshi territory!

While optimizing the newly conquered realms, I continue to push into Hida #6 from Mino. They won't have the same weapons advantage that they had coming from Owari, but they won't need it; my force outnumbers them 3:1. This converts the entire Asakura territory to me. With them out of my way, Owari can, quite safely, invade Tokugawa's realm with their entire army. Sayonara, old friend.

 

And honestly, the rest of the game just isn't all that interesting to write about. So I won't. I isolate the rest of my rivals and conquer them one-by-one with overwhelming invasion forces by the end of the year.

The last, hilariously stacked battle against Uesugi in their little alcove.

 


 

Some additional notes:

A non-aggression pact costs both lords 10 gold and sets a diplomatic relations value to 70. It will always be accepted as long as this value is not negative, but it does not guarantee non-aggression! Essentially, it means that if the lord decides to attack you, there's a 70% chance of changing his mind. This value trends 10 points toward zero every spring, and I'm not sure what makes it go into negative.

Typhoons, like plagues, have a 25% chance of affecting each province on the map. The effect is to reduce productivity to [Flood Control]/220 of its original value. It also reduces peasant wealth by 1-5 points.

The AI has a routine to evaluate potential invasion targets, and part of it is estimating the regional strength. If a region has more rice than soldiers, then it evaluates the strength as [Soldiers]². Otherwise, it is evaluated as [Soldiers]*[Rice]. This is doubled if the lord is present. They tend to attack weak provinces if they have a stronger adjacent province.

Ninjas will do damage to a target provinces' army loyalty, training, peasant loyalty, and wealth. The amount decreased is five points per ninja. 

Tuesday, May 5, 2026

Nobunaga's Ambition: Won!

Three times I was snuffed

Two embers still burn within

One Shogun will rule 

 

1560

Tokugawa's stats, not mine

Even on the second-lowest difficulty, Tokugawa is still the one to be wary of, and yes, his stats are still a lot better than mine. Funny that his constitution seems to be the one random variable; everything else is fixed by difficulty.

I begin with familiar actions. Put everything I've got into the town. The next year, rice prices are high, and following Scribe's advice, I put my entire collections into dams, in the hopes it will bring a better rice yield.

And it is a good investment. This time, only one soldier deserts after his comrades eat everything! Next season I distribute coins to the peasants to boost wealth and loyalty, and the harvest becomes a surplus; no more desertions.

 

Now that my little province is self-sufficient, it's time to grow. The harvest can support 16 soldiers, but I'll need to pay them too; I put my gold into town and gift the rice surplus back to the peasants. War starts breaking out by 1564, and territories change hands, but I'm left alone, and the year's tax season brings in 54 ryo and 24 koku.

Let's see how I stack up against my neighbors.

 

Province Owari #17 Iseshima #13 Mino #9 Mikawa #8
Clan Oda Kitabatake Saito Tokugawa
Age 30 23 39 22
IQ 39 78 62 120
Constitution 67 60 68 61
Ambition 59 89 89 120
Charisma 58 96 71 120
Luck 50 56 80 120
Gold 58 4 1 6
Rice 24 25 87 34
Debt 0 0 0 0
Towns 2 2 2 2
Productivity 40 20 64 35
Flood control 89 153 172 185
Peasant loyalty 127 87 67 86
Peasant wealth 146 80 90 110
Army size 9 7 12 11
Army loyalty 83 82 59 104
Training 177 75 129 120
Arms 100 87 87 60

 

I am not worried about Kitabatake at all. In fact I'm pretty sure I could march in and take their land if I didn't care about leaving Owari completely exposed. I'm not too worried about Saito either as long as I can match his army size and avoid a repeat of the last game (and I can). Tokugawa is a bit more intimidating.

I hire three soldiers, negotiate a non-aggression pact with Tokugawa, and put the rest of what I've got into cultivation, because my production stat feels a bit left behind. Rice goes to the peasants.

 

1565 

It's time to start thinking about conquest. The clans are already fighting, and some players have been eliminated. I assemble a strategic map, annotated with the controlling clans and their total army sizes.


Takeda is looking a bit intimidating, and makes Saito a risky take, but those 26 armies are spread between two provinces.

My first target will be Saito. I will want to have at least 26 armies to take it with, and at least 10 to leave behind. I'm going to need more money, and thankfully, I'm rich in rice and the merchant is here. Rice becomes gold, gold becomes soldiers, gold goes into more cultivation... and a typhoon immediately wrecks whatever good that did. No matter, I invade Mino to the north, and win very easily.


1566 


While I was fighting, Takeda was wiped out! And most of the regions to the east have strengthened. Imagawa is looking very dangerous. Tokugawa is not.

My plan will be to continue expanding north, split Japan in half, and prey on my neighbors to the west first. Owari is not vulnerable. Mino is. I move there, leaving a vassal in charge of Owari, and propose a non-aggression pact with Imagawa. With me goes Owari's entire rice surplus, which I exchange for gold and dump into the town center for more gold.

A few more turns of building up these provinces, and the map now looks like this.

 

1569 


Slight change of plans - I realize that if I invade Asakura from Mino, this will leave Mino vulnerable to its neighbors. But if I expand westward from Owari, I can fully commit; Owari has no hostile neighbors except Tsutsui. Iseshima #13 falls very easily indeed, and then we go onward to Iga #12 and Yamato #10, crippling the clan.

Sheer numbers, not skill, carry me to easy victory.

 

I'd show screenshots but it's just not all that interesting; I beat them with sheer numbers, not skill.

 

1572


Asakura have gotten quite strong in their sequestered, not-so-little province! I consider them my only threat right now, and focus on building up my territories and sending troops and rice to Mino #9 so that I can invade, while making sure that Tsutsui and Azai can't hurt me.

In 1573, Azai attacks me at Iga #12, and they're able to inflict some major damage on the troops despite my best efforts to match them for army size and skill, but I hold out in the relative safety of my castle as they starve to death outside.


Omi #11 is mine, and Asakura's army size in Echizenwakasa #5 mysteriously shrank from 1005 to 62, so I march in and take it.

 

1574


Tsutsui is all that remains to be conquered in the west, and I do with the greatest of ease.

They basically commit seppuku on our spears.

 

I start concentrating my wealth and soldiers east to Mino #9 and begin chipping away at the Honganji empire - to my surprise, the whole place falls in one stroke, and we push on to take Kaishinano #16 from Imagawa by the end of the year.

 

1575 


Hojo is having trouble feeding all of those soldiers! No problem; I can feed what's left of them. I do that, and win the game by summer. I honor my non-aggression pact with Tokugawa Ieyasu and kill him last.

 

GAB rating: Average. Nobunaga's Ambition was a tolerable experience once I survived long enough to defend myself, but not an especially interesting one. I can't say much that wasn't already said by Scribe; there isn't anything quite like this in 1983, and later incarnations definitely influenced the Total War series, but here, the various systems just aren't deep enough to interact in non-trivial ways. War is a major weak point; there is no tactic for dealing with a +10 strength doom stack other than digging in and hoping your provisions outlast his, and otherwise, you can win pretty much any encounter by holding out in advantageous terrain or by swarming the lord's position. The economic layer is where games are won and lost, and it seems to me that there is definitely an optimal way to play it, which I intend to explore in my next (and final) post on the subject.

I see a lot of similarities to Hamurabi and Santa Paravia, and the more I think about it, the more sure I become that Hamurabi, at least, must have been familiar to designer Yoichi Erikawa. The turn-based kingdom management, the simple resource management model, fluctuating rates of goods, and random disasters are all here and work so similarly that it doesn't seem like a coincidence. I can't find any record that David Ahl's seminal BASIC compilation was available in Japan at this time, but as I understand it, magazines like ASCII, which regularly printed type-in programs, were the main resource for computer hobbyists at the time, and it seems only natural that Hamurabi would have reached an audience this way. Somebody tell me if this sounds crazy, especially if you're more knowledgeable on this subject than I am!

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