Rumors? A rumor that makes sence.(Concentration).

There is nothing more stupid and retarded again by methods and tools used for concentration.
Techniques like western yoga in which you have to literally stretch your body till your balls are going to fall from their place thinking that energy unblocks from the body,
Energy that is locked in the first place,
Methods of meditation,like they are a lot of people who truly meditate,
crystals which help focus supposively despite the fact that even if is a good quartz
You gonna use it like a three years old boy is going to use a knife,
Drugs and consumables,in which if you don't have the honesty to admit that you only wanted to get high(and there is nothing wrong with that) you gonna get "convinced" that a result is going to occur(which is not) and then further convince the rest of the bunch of idiots that you were right in the first place.

Yoga is not going to work because it demands a hollistic approach to life and a body ready for it,
Meditation has nothing to do with concentration(at least the one regarded to senses)
Crystals amplify an ability in rare cases if you already have a progress (which i presume you don't) and of course you can tune yourself with one (which you can't)
And drugs just bring yourself to an "induction" state in which the minds "sinks" bad
Forgeting that you have to bring the context of non concious realms to the surface
Not sink yourself in them.

So all of these methods is the example of a car with a motor stripped in pieces in which you find yourself just spraying oil on her.
And on a good assembled motor this oil would be useful.
In the best case a person would manage to assemble pieces in a random way so the car would move a bit,but even that is not enough for function.

And to the person which seems to be honest to himself to a degree,soon he is going
to realize the failure of these methods and see that a huge amount of effort is nessesairy for a change and he's going to abandon things that are going to leave him
without a result.

So there is a mountain to climb.
And a very good tactic is to learn how the mountain looks so you can make a progress.

what is concentration?
The most immediate tool of realization is the senses.
Senses are gathering huge amount of informations in no time.Also they are tools
OF IMMEDIATE FOCUS.
If we take the law "as the inner the outer" propably senses can be turned inwards
The same way they turned outwards.
But senses introvert function is very difficult to even realize so the attention should
be turned to the direction of the extrovert function which if develops gonna reflect on the introvert one.
And the introvert motion of the senses is a key of realization.

And the exercise occurs:
Now when somebody use a sence of himself in order to concentrate he tends to isolate his sence.
For instance:
When you wanna see something at a distance you tend to focus into that object through your eyes and at the same time the mind and other senses stop.

But there is the ability of the human mind to do many things together.

So the exercise occurs:
The person should start focusing at the same time in more then one senses.
The most two immediate senses are the vision and hearing.
So the person should focus on these two at the same time.
Once this starts to work the most immediate feeling is gonna be close to the one
that happens in a deja vu.
Once these two senses (after an amount of time of course)
Are second nature to the man the person should add a sence once at a time
taste first as the tongue has the ability to sense the mouth without a movement,
touch and last smell.
Smell last because she's tuned with breath as a function.

Subject of this exercise is the Concentration and tuning of the senses.
If this achieved first of all the person's awareness to his enviroment is increased dramatically.
Second if the person manages that sooner or later this is going to reflect on the inner
self as a mirror of the outer.

Infact it is been said that because the secret of true focusing HIDES IN THE SENSES THEMSELVES talents like telekinisis happen by that tuning.

Infact it is been said That even obe's Are a result of that exercise as the introvert motion of the senses can deattach part of the etheric from the body without effort
or confusion.

Good luck