As I'm learning to master the first jhana one must do two things, master the five masteries & be able to extend the sign. For the masteries,
• Mastety Of Adverting ×Turning your attention & focus on any jhana factor after! anywhere,time or place
• Mastery Of Attainment × Entering jhana concentration quickly, Anytime you wish
• Mastery of Resolving ×Staying in the absorption for as long as one wants.
• Mastery of Emerging × Emerge from The Jhanas Quickly
• Mastery Of Reflection ×Looking at & learn each thing you did to enter each jhana factor.
Please tell me if I'm incorrect. Now for extending the sign. I don't truly understand how to do such a thing, or even what it is. Here's a passage from the book I'm reading.
The perfecting of the first jhana involves two steps: the extension of the sign and the achievement of the five masteries. The extension of the sign means extending the size of the counterpart sign, the object of the jhana. Beginning with a small area, the size of one or two fingers, the meditator gradually learns to broaden the sign until the mental image can be made to cover the world-sphere or even beyond (Vism. 152-53; PP.158-59).
Can someone please elaborate for me please. I need to understands what the counter-part sign is & how to extend it. Is it a mental image you have? So a kasina ot any other mental image you form?