One of Buddhist master wrote this:
If thoughts arise, remain present in that state.
If no thoughts arise, remain present in that state.
There is no different in the presence of either state.
The last sentence is the one that will make you able to meditate without any focus.
Another Buddhist master said this:
Things appear without really existing.
That is the one that you need to prove in vipassana. Once you get that, you will get that there is no difference whether you have thoughts or no thoughts, because both state are same. Both are without really existing.
Blue glass and red glass are different, but they are same, just glass.
Diamond and a brick are different, but both are same. Both are transient, without any core. Both appear without real core.
If you can eliminate the strong believe of core by witness it and prove it for yourself that actually there is no core, you will be able to meditate without any object or any focus.
Sometime you may feel that oh today my meditation is excellent. No thoughts and so smooth.
Next day, oh my meditation is so bad. So many thoughts.
This will occur if don't realize that actually those two state - having thoughts and no thoughts - are exactly same.
How can both be the same? The key is in your witness of no core or no self in whatever things you are witnessing.
Once you get it, there is no sih thing called bad meditation, even a meditation with million of thoughts are perfect. Because you know vividly those million thoughts are transient, exactly same with the state of no thoughts.
If you can know the no core,
Meditation with million of thoughts, millions of feeling are just same with meditation without any thoughts (the meditation that you always think is ideal).
Both are transient without any core.
So, whether you have thoughts and no thoughts, where is the problem?
Million thoughts are transient, no core, no self.
No thoughts are ALSO transient, no core, no self.
Why meditation with no thoughts are something special?
There is nothing special in it. There is no reason why this state is ideal. Both state are just same thing, transient, no core, no self.
You are actually always and always in te perfect state of meditation, only if you can understand both are actually just same - transient without any core or self.
Perfect without any effort.
Please prove this with yourself Experientally whether this is true or not.
I am not here nor there.
I am not right nor wrong.
I do not exist neither non-exist.
I am not I nor non-I.
I am not in samsara nor nirvana.
To All Buddhas, I bow down for the teaching of emptiness. Thank You!