Jhãna is the 1st Mental Absorption! Jhāna is Pāli: In Sanskrit = Dhyāna, in Chinese = Chān, in Japanese = Zen.
Preliminaries: Purified Morality => Clear Conscience, innocence & the mental elation thereof. Guarding the Senses => Absence of Temptation, greed, desire, & attraction. Clear Comprehension => Acute Awareness & Absolute Mental Presence. Contentment => Calm & Stilled Satisfaction even with nothing. Joy & Happiness.
Mental Factors of Entry: 1: Absence of any Urge of Desire 2: Absence of any Aversion of Ill Will 3: Absence of any Lethargy & Laziness 4: Absence of any Restlessness & Regret 5: Absence of any Doubt & Uncertainty 1: Presence of Directed Thought 2: Presence of Sustained Thought 3: Presence of Rapturous Joy 4: Presence of Pleasurable Bliss 5: Presence of Single-Pointed Focus
Subjective Experience: Intense presence & awareness. Effortless, undistracted, & focused thinking. Attention anchored even at ease at any chosen object. Mind is fixed & unified. Result of chain of reasoning arguments is always reached quickly & successfully. Body is without any pain & is felt like being a feather inside a big empty silent hall. There is Joy, Bliss and Happiness mixed into Solid Calm like a Smiling Mountain!
Stages: 1: Directing (adverting to sign of serenity). 2: Attaining entrance & stabilizing that. 3: Prolonging & controlling duration. 4: Emergence from absorption. 5: Reviewing (looking back on).
Grades: I: Access Concentration like in neighbourhood approaching (upacāra-samādhi). II: Full Absorption Concentration fixed & anchored on object (appanā-samādhi).
Techniques which can induce Jhāna Absorption: Awareness of Breathing (ĀnāpānaSati) Basic Entirety Object (Kasina) Inner Organs & Corpses (KāyagatāSati) The 4 Infinite & Divine States (Mettā) The 4 Formless States (Āruppa)
Buddha Said: Having momentarily eliminated the five mental hindrances of: Sense Desire, Ill Will, Lethargy & Laziness, Restlessness & Regret, and Doubt & Uncertainty, defiling imperfections of the mind that obstruct concentration & understanding, quite secluded from sensual pleasures, separated from disadvantageous mental states, one enters & dwells in the first Jhāna absorption of directed & sustained thought joined with joy & pleasure born of secluded solitude. One makes this joy & pleasure born of secluded solitude pervade, perfuse & fill the entire body so that all parts is thrilled by this joy & pleasure born of secluded solitude. Even as a clever barber or his apprentice would put soap powder in a brass basin, sprinkle it with water, gradually knead & moist it into a ball of foam soaked thoroughly everywhere inside out yet without dripping so too he pervade, perfuse & fill his entire body so that all parts is completely drenched with joy & pleasure born of secluded solitude.
