Best Strategy Game for the NES. Period.
Nobunaga's Ambition is similar in many ways to the original Romance of the Three Kingdoms, and the later versions of the game moved in the same directions. The game puts you in the position of being a Damiyo in Japan, during their Warring States Period. Like RoT3K, your goal is to take over Japan, and crush your rival damiyos. Now, obviously, you can't do this without a certain degree of political finesse, to keep some of your rivals at bay while taking care of others. All alliences are temporary, but the length varies by which alliance you choose. You can either marry one of a rival warlord's daughters (or marry one of yours off to him - don't wory, you'll always have enough), or sign a truce. As blood is thicker then water, alliances through marrage last longer.
The game is turn-based, with each province having a spot in the queue. When your province comes up, you get various options, to train your men to improve their skill, improve the provence to increase food production (and damage caused by typhoons), raise and lower taxes to raise money (at the cost of peasent happiness), hire or raise armies, as well as equipping them. And send ninja spies to neighboring provences to destabalize the populace, lower troop morale, determine troop strength, or even assassinate an enemy general. These cost money and, if caught, the relationship between you and the warlord of whatever province you're spying on can become strained. Also, you can send troops off to war with your rivals. Armies consist of infantry (pike-men), cavalry, or musketeers.
When you invade a neighboring provence or are invaded yourself, the game goes into what I call Tactical Mode. Both sides place their troops on a tile map that is laid out similarly to a hex grid (in that every tile, with the exception of edge tiles, touches 6 other tiles). Units can only be moved one square per turn, except for cavalry, which can be moved two. However, you cannot move through squares occupied by other units, including friendly ones. Battle strategy ultimately goes down to how well trained your troops are, and where you position them on the field.
Also, despite the recent depictions of Oda Nobunaga in recent video games, including Koei's own game "Samurai Warriors", there are no supernatural powers in this game. The outcome of each battle lies only in the hands of your troops, and in your own skill as a general.
The graphics in the game are sub-par, even for a NES game. Colors are faded, along the lines of something you might expect to see in a Commodore 64 or Apple IIe game. There is also very little sound to speak of, though, in the case of this game, and the console it was on, that was a blessing.
In general, one game, depending on skill level, is pretty long. The AI is aggressive, and ruthless. Making an alliance with an AI Player will essentially give you a reprieve only until that AI Player's offencives on other fronts peter out. At which point, it's your turn. The number of options in the game for improving your troops and your providence can be fairly daunting, hence the large learning curve. Once you get the hang of things though, you'll find hours of enjoyment. It does support battery saves though, so you don't have to worry about playing through the game all at one whack.
This game is fairly hard to find. However, if you find it, or any of the later games of the series, it is definitely worth the money. The later games in the series improve the game in various respects, including, if not larger maps in Tactical Mode, then smaller tiles, allowing for more options for maneuvering your trooops. Still, the significance of this game in Koei's history, as well as the history of strategy gaming on the console, cannot be underestemated, and this game is a worthy addition to any gamer's library.