[856] Therein, what is skill in the elements (dhātukusalatā)? The eighteen elements (dhātu): the eye element, the form element, the eye-consciousness element; the ear element, the sound element, the ear-consciousness element; the nose element, the odor element, the nose-consciousness element; the tongue element, the taste element, the tongue-consciousness element; the body element, the tangible element, the body-consciousness element; the mind element, the dhamma element, the mind-consciousness element. That which is skill in the elements with regard to those elements — wisdom (paññā), understanding, … non-delusion (amoha), investigation of dhammas (dhammavicaya), right view (sammādiṭṭhi) — this is called skill in the elements.
Therein, what is skill in attention (manasikārakusalatā)? That which is skill in attention with regard to those elements — wisdom, understanding, … non-delusion, investigation of dhammas, right view — this is called skill in attention.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.