Recently, I helped a friend to review his game. I noticed that his mechanics is good but he doesn’t understand “convergent point”. Convergent point is a basic concept which is extremely important. Unlike mechanics like macro and micro, it is something that does not require repeated practice for improvement. Once you know it, you know it.

Basic idea

Convergent point refers to a benchmark in terms of the production buildings you should have based on the number of bases you own to have optimum production. If you have more buildings than the convergent point benchmark, not all buildings are producing. For example, you cannot produce from ten barracks constantly if you only have one base. Conversely, if you have less buildings than the convergent point benchmark, you are banking too much resources.

It is important to note that convergent point assumes constant production from every building including the command centres. Unlike other races, Terran has a linear production cycle. That is, you just keep producing constantly. For Protoss, you cannot keep producing Stalkers and tech up at the same time. Furthermore, the warp in mechanic allows you to have a sudden “burst” of units, and that makes convergent point to be more flexible than Terran. As for Zerg, you need to choose between units and workers from the hatchery, and hence, there isn’t exactly a convergent point. Therefore, in comparison to other races, getting the convergent point right is crucial for Terran.

Convergent point is best presented based on the number of bases you own, and it gets more flexible as the number of bases increases. This is because if you have four or more bases, it is unlikely that you produce constantly since you will reach the 200 supply cap. Then, you will bank up. You will resume production after you have lost your units in a big battle. It will be wise to have prepared extra production buildings so that you can re-max quicker. Therefore, convergent point gets less clear when you have four or more bases as there are other factors that can affect it such as re-max capability and tech switch.

Convergent point can vary according to your overall game plan. If you decide to all-in with two bases, then you can afford to have more production buildings than you do if you choose to get a third command centre. I will elaborate more below.

Note: The below variations are not collectively exhaustive. They are the main stream ones.

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One-base convergent point

No expansion

– 3x Barrack (4x without gas)

or

– 2x Barrack
– 1x Factory
– 1x Starport

Expansion

– 2x Barrack

or

– 1x Barrack
– 1x Factory
– 1x Starport

Explanation

You cannot play mech with one base, so it is about the number of barracks you have. If you do not expand, then you are doing a one base all in. You can do a three barracks stim timing, four barracks Marine and Scv all in or a 2-1-1. It is possible to transit and expand by cutting production.

If you plan to expand, you cannot go beyond two barracks. So it is normal to see one barrack expand, or two barracks pressure into expand. For 1-1-1, it is possible squeeze out 400 mineral. Importantly, it is not a must to reach the convergent point for one-base before you expand. You can expand with one barrack. I will elaborate on this in part 2.

Two-base convergent point

No expansion

– 5x Barrack (no gas)

or

– 5x Barrack
– 1x Starport

or

– 4x Factory

Expansion

– 4x Barrack

or

– 3x Barrack
– 1x Factory
– 1x Starport

or

– 3x Factory

Explanation

Five barracks on two bases is a MarineKingPrime strategy. If you want to apply Marine pressure and expand behind it, you should have four barracks instead which is something that Puma liked to do in the past for TvP.

Quite often people mention whether they prefer two more barracks or a third command centre in TvP. It is a decision based on convergent point. Usually when you have two bases in TvP, you will produce bio from three barracks and Medivac from a Starport. By around 9:00 – 10:00, you have to decide if you want to be aggressive (two more barracks) or economical (3rd command centre).

It is possible to play mech on two bases. For a period of time, Korean Terran in GSL tends to do four factories all in on two bases. It is typical to have three factories and expand for mech. I did not consider starport as part of the convergent point for mech because the production depends on the situation.

Three-base convergent point

– 8x Barracks
– 2x Factory
– 1x Starport

or

– 8x Barracks
– 2x Starport

or

– 5x Factory

Explanation

There is no such thing as “no expansion convergent point” for three bases. When you go for three bases, you play a macro game. You should take the fourth if possible.

Eight barracks, two factories and one starport is mainly for TvT and TvZ. It is possible to have three factories, but that may affect the production from other buildings.

Eight barracks and two starport is mainly for TvP. The second starport is a reaction to Colossus tech.

Five factories is obviously for mech. Again, starport is not included for the reason mentioned above.

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Part 2 will continue with more advance concepts of convergent point.