This very first version had good success and was quickly followed by more by the same authors.
This version had a surprise round that did not involve any initiative. If the Monster or the Party could surprise their opponent, then that first round was a free attack for the party that surprised the other.
Whether one side was surprised was determined by a roll of a 1d6 and on a 1 or 2, surprised it was. There was no adjustments of any kind. However, surprise was only possible if the other party did not have blatant light, was not making loud noises, etc. Whatever would cancel the possibility of a surprise attack.
If the Monster or Player has 2 attacks per round, they could perform both attacks in a surprise round.
Following rounds will be handled using Initiative to determine who goes first.
Note that an oponent with 2 attacks, such as a Unicorn, that had a Suprise round and wins the next round initiative ends up with a total of 4 attacks before its adversary has a chance of doing anything. That really gives a chance for the suprise party to do a lot of damages and possibly kill the characters.
Each character and each monster gets a roll. The ones with the highest roll goes first.
This version has an adjustment using Dexterity:
→ Add one to your 1d6 roll if your dexterity is 13 or more.
→ Subtract one to your 1d6 roll if your dexterity is 8 or less.
Note that the "Subtract One" was actually an optional rule. In other words, you could avoid losing one point on your initiative roll. The "Add One" was not optional.
Of course, Monsters had the same advantages and disadvantages as the players. However, the rules did not include the Dexterity Score (or any score if that matter) of monsters.
There was nothing in those rules about what to do when both parties would roll the same number.
So if you rolled a 3 and had a dexterity of 15, you would get an initiative of 4.
The gobelin attacking you rolled a 4 and had no dexterity adjustments.
You both ended up with the same number... and that meant neither parties had the highest roll.
So... What would you do?
A first way to resolve a tie would be to re-roll until you break the tie and one of the parties has a higher number.
This was not in the rules but came out in a magazine at some point later and generally became the way of doing it in future versions.
This is a solution we used at our table with Advanced Dungeons & Dragons (a.k.a. 1e).
Whenever a tie would show up, we'd play it as if both parties could simultaneously hit each others. The really cool thing in this case is that both parties could both die or at least become unconscious.
I always thought this was the best idea because this would totally increase the tension in the game. So many times we survive such a monster blow by just 1 hit point!
One important aspect of this version of the game was the fact that initiative would be re-rolled on each round. This created a sense of possible weakness whenever the users would get low on hit points and spells and would lose initiative...
At the same time, it was somewhat tedious to keep track. But the initiative using just 1d6, so it was just easy enough to order each member of each party.
Actually, later versions offered this method too, it became optional, though.
The one thing I noticed quickly was the fact that rolling a 1d6 would not give you much room to win or lose initiative. We often would end up with ties and winning initiative was generally much more random than one would expect in the real world.
Also surprise would cancel initiative on the first round and dexterity could give you a +1 or -1, that were the only two factors taken in account in the very first version.
In the very first Basic Set version of Dungeons & Dragons, it was clearly spelled that the characters and monsters could do three things in combat, in that specific order:
One: move around as per their movement capability; riding, swimming, and flying capabilities were already included.
Two: attack by missiles (i.e. arrows, javelin, etc.) or spells.
Three: attack by melee weapon.
Note: any thrown object was considered a missile, even if it was a melee weapon such as an axe.
An interesting side effect of this was the fact that magic-users and clerics would likely cast a spell before attacks by melee weapons would be resolved. So they could end up wasting a spell.
In a way, this order was a little like having a sub-initiative within the round and you would go before or after a peer because of the type of attack you would perform.
I have not played this one enough times to tell, but in a tie, this sub-initiative could also have interesting side effects where a spell caster could blow a dragon with a nice fire ball before getting eaten...
Already in this version, saving throws were automatic. They did not require any initiative.
In other words, a player attacked by the breath of a dragon can roll a saving throw at that time, whether they already had their turn or not on that round.
In this older version of the game, spell casters could cast their spell once it was their turn, whether they got hit or not by their adversary.
This was a nice bonus compared to newer versions where your spell is usually wasted on a hit by your opponent. Although I have to agree that if it takes you some time to cast the spell, it makes sense that you would lose it if hit.
However, that meant that winning initiative or not did not matter too much for a spell caster (outside of the fact that they were still quite likely to be killed with just one blow and so when their turn comes they are dead and cannot cast their spell anyway.)
The current version of Turn Watcher, our initiative and hit point tracker desktop software, has no support for the very first version of Dungeons & Dragons (1974). We have not heard of one person asking for such support either.
Remember that Turn Watcher uses a 1d20 to roll initiative. So if you are a purist, it would not work for the original which used a 1d6.
All of that being said, you could play the old version with initiative from 3.5e. We think that Initiative handling in version 3.5e is the first version that was really good/sensible so yeah... you probably should use Turn Watcher even for the Original D&D version!