black jack optimal strategy

This only occurs on the first deal. The simplest rule in Blackjack is that if the face up card of the dealer is 7or higher, the player must consider it likely the hole is a 10-value card, and must hit if the player hand is 16 or less. The Rules of Blackjack
If you are counting cards and know what is there, well then take the insurance, otherwise stay away from it. Managing your money properly is the major criteria while playing blackjack, as no technique or method can win you money unless you effectively deal with your bet. Blackjack pay outs of 6 to 5 i.e. It was invented over 200 years ago.
There are two kinds of blackjack games played in casinos, which can use up to eight decks. If you are counting cards and know what is there, well then take the insurance, otherwise stay away from it.