Why didn't the buddha know how to attain first jhana when he already attained dimension of neither perception nor non Perception from his previous teacher(rama)?

[paul1]

If the sutta is read carefully the focus is not on the attainment of jhana but on the pleasant feeling that accompanied it:

"I thought: ‘So why am I afraid of that pleasure that has nothing to do with sensuality, nothing to do with unskillful mental qualities?’ I thought: 'I am no longer afraid of that pleasure that has nothing to do with sensuality, nothing to do with unskillful mental qualities "—MN 36

This then relates to the second tetrad and second foundation, where pleasant feelings not of the flesh are not to be feared, but developed.

See my post here:

The Role of Blissful States in Buddhist Meditation

I recently read this book The Role of Blissful States in Buddhist Meditation. In that book the author attempts to construct what meditation looked like before and after the time of the Buddha. He draws on the Vedas, Upanishads, Buddhist, and Jain texts. One of the interesting things he mentions is how the Buddha was unique (at that time) in describing blissful states as part of meditation (like piti when talking about jhana). This got me thinking about the role of blissful states in Buddhist…