All Access

Sayadaw takes a left turn on PAGE FOURTEEN and says that to see the types of materiality, one must be able to have 'strong and powerful concentration'.  He introduces the following types: 

• Concentration of the Jhanas, using for example mindfulness of breathing and the ten kasinas, or
• Access concentration using four-elements meditations. 

Jhanas are successive states of deeper and deeper absorption in meditation and 'Access concentration is,  well, a piece from Access to Insight offers some information, stating that there are eight steps to concentration, which are:

The eight steps are named: counting (ganana); following (anubandhana); contact (phusana); fixing (thapana); observing (sallakkhana); turning away (vivattana), purification (parisuddhi); and retrospection (patipassana). These eight cover the whole course of meditative development up to the attainment of arahantship.

I'll stick with where I've felt myself to be, which is counting, following the breathing and then some of contact and 'fixing', although these terms are brand new to me:

(iii) Contact and (iv) Fixing

These two aspects of the practice indicate the development of stronger concentration. When the mindfulness of breathing is maintained, the breathing becomes more and more subtle and tranquil. As a result the body becomes calm and ceases to feel fatigued. Bodily pain and numbness disappear, and the body begins to feel an exhilarating comfort, as if it were being fanned with a cool gentle breeze.
At that time, because of the tranquillity of the mind, the breathing becomes finer and finer until it seems that it has ceased. At times this condition lasts for many minutes. This is when breathing ceases to be felt. At this time some be come alarmed thinking the breathing has ceased, but it is not so. The breathing exists but in a very delicate and subtle form. No matter how subtle the breathing becomes, one must still keep mindful of the contact (phusana) of the breath in the area of the nostrils, without losing track of it. The mind then becomes free from the five hindrances — sensual desire, anger, drowsiness, restlessness and doubt. As a result one becomes calm and joyful.
It is at this stage that the "signs" or mental images appear heralding the success of concentration. First comes the learning sign (uggaha-nimitta), then the counterpart sign (patibhaga-nimitta). To some the sign appears like a wad of cotton, like an electric light, a sliver chain, a mist or a wheel. It appeared to the Buddha like the clear and bright midday sun.
The learning sign is unsteady, it moves here and there, up and down. But the counterpart sign appearing at the end of the nostrils is steady, fixed and motionless. At this time there are no hindrances, the mind is most active and extremely tranquil. This stage is expounded by the Buddha when he states that one breathes in tranquilizing the activity of the body, one breathes out tranquilizing the activity of the body.
The arising of the counterpart sign and the suppression of the five hindrances marks the attainment of access concentration (upacara-samadhi). As concentration is further developed, the meditator attains full absorption (appana-samadhi) beginning with the first jhana. Four stages of absorption can be attained by the practice of anapana sati, namely, the first, second, third and fourth jhanas. These stages of deep concentration are called "fixing" (thapana).

Well, to be honest, no real counterpart sign but some weird and wonderful things have occurred temporarily.  I love this stuff.  It is quite the paradoxical effort to stay with concentration.