I have to confess this is favorite and go to old school system. It hits all the right check boxes for ease of play, ease of house ruling, and ease of conversion. So you may take this as a little biased. Well, I do have to have a favorite and this is it.
I guess I should start with the “flavors” of Swords & Wizardry. Yes, it does come in flavors. Overall, Swords & Wizardry is based on the original little brown books and their supplements. Swords & Wizardry Complete is version that is actively being supported by Frog God Games. Like the title says, it’s the most “complete”. You get all the common classes: Assassin, Cleric, Druid, Fighter, Magic-Uesr, Monk, Paladin, Ranger, Thief. And the most common races: Humans, Dwarfs, Elves, Half-Elves, and Halflings. Then there’s Swords & Wizardry Core. It has the four basic classes and four basic races (no Half-Elves). Overall the game mechanics of Complete and Core are the same and most of the differences are minor. Then there’s White Box. It’s based specifically on the first three little brown books. So only three classes (No Thieves) and the four basic races. The other difference is that primarily uses only d20’s and d6’s.

All of the old-school games are largely compatible as I’ve said. Swords & Wizardry give the option of using Ascending or Descending AC. So that they way you want. One thing that it did add is the Single Saving Throw. Instead of 3, 5, or even 6 Saving Throws. Characters and monsters have a single Saving Throw. For characters, the base is determined by class/level and then there additional modifiers based on race and class. There is the option to use the good old five Saving Throws but I happen to like the Single Save.
Let me tell you why. First when characters are leveling up, the players only have to change one number. As a GM, there are some weird situations that it’s an quick and easy solution to just have the player make Saving Throw and not really worry about which one. Also as a GM, it really helps speed up combat. It makes the monster stat blocks so much quicker when I just have a number there and not something like “Saves as a 3rd Level Fighter”. Crap, let me look that chart up. As a matter of face, I’ve used Swords & Wizardry monster stat blocks while running other games. Yes, even 5th Edition.
Because of the clear and simple rules plus that Single Save, it makes house ruling and home brewing really a breeze. I put up a bunch of the stuff over on the Downloads page plus there posts all over this blog and many, many more with great and inspirational material. So there’s plenty of fan material out there as well as a lot of Third Party Publishers.
There’s lots of Third Party Publishers out there (myself included) and I know there’s probably some that I’m going to miss. I apologize for that. And with all this material being created, you don’t have to stick to just fantasy. The rules have been converted into all the major genres.
Barrel Rider Games has lots of stuff for Swords & Wizardry (and other games). White Star and their White Box line are awesome.
Check out Sine Nominee for
Want some WWII action? Well there’s Operation White Box. Spies? Got you covered with White Lies. You want a more Swords and Sorcery type game? Then there’s Crypts & Things. There’s more out there and I”m just scratching the surface here.
There a couple that deserve some special attention. Swords & Wizardry Light/Continual Light and Whit Box: Fantasit Medieval Adventure Game. Swords & Wizardry Light is the brain child of Erik Tenkar. It’s a fast play introductory game. It’s prefect to to teach beginners or for a quick pick up game. Swords & Wizardry Light is based on the White Box rules and covers Levels 1 to 3 and does it in just four pages for a complete game. Continual Light takes the game to higher levels and has also some 3rd Party Publishers offering material. Swords & Wizardry Light is free while Continual Light is dirt cheap.
White Box Fantastic Medieval Adventure Game Game by Seattle Hill Games is also dirt cheap for hard copies and free as a PDF. It’s almost identical to Swords & Wizardry White Box but it adds the Thief and a few other minor mechanics and works perfectly with other White Box materials.
And if you’re still with me, the PDF for Swords & Wizardry (and some of the others) is FREE! Legally that is. And you can’t beat that price. You can grab up all sorts of stuff on Drivethrurpg, Lulu, Frog God Games, and lots of other places around the net.