When did Arjuna fight Bhishma for the first time?

Arjun fight with Bhisma for the first time in the war of Mahabharat.

Mahabharat is the biggest war ever. It was fought between Courav and Pandav. Bhisma was the great warrior and he was the Great grandfather of Arjuna and Bhisma had the gift of euthanasia no one can kill him without her decision.

Bhisma knew that the Kauravas were walking on the path of Iniquity

So Bhisma decides to euthanasia and even before the war between Bhisma and Arjuna Arjuna came to Bhisma and told that he does not want to fight but Bhisma Explained him that he should fight and Bhisma also tell that he wants to die with your hand.

Why does Bhishma not give up Prana even after lying on the bed, while his entire body is shattered with arrows, yet he does not die due to euthanasia? Bhishma knew very well that the soul attained salvation when he gave up his life after the succession of the Sun, and he would go back to his own world and be free, that is why he waited for the sun to pass.

Bhishma told that he would leave the body only when the sun is Uttarayan because he has the will of euthanasia from his father Shantanu and he cannot leave the body unless he wishes. It is also said that surgeons are brought to cure Bhishma, but they return him and say that now my last time has come. It is all in vain. Sharya is my funeral pyre. Now I am just waiting for the sun to rise.

Later, on the Uttarayan of the Sun, Yudhishthira, relatives, priests and other people reach Bhishma. The eldest father said that it has been 58 days on this Shastra. Shukla Paksha of Magh month came from my fortune. Now I want to leave the body. After this, he gave up his body by lovingly leaving everyone. Everyone started crying after remembering Bhishma. Yudhishthira and the Pandavas placed the dead body of Pitamah on the pyre of sandalwood and cremated.