Doran's shield helps jax regenerate some hp in battle and have bonus health, it has a good effect on jax specially in hard lanes. no jax is complete without its signature item guinsoo's rageblade with its bonus attack speed, damage, and ap. Phantom dancers gives jax bonus movement and attack speed too easily catching up with targets.Gunblade can be used to slow enemy with combo to phantom dancer and gives ap, damage, and life steal. black cleaver bec our jax is an attack type so negative armor and bonus attack speed. Finally bloodthirster for additional damage for health and bonus life steal.

Using assassination jax you need to focus on weaker and easy to kill opponents specially high ap mages which can be really hurt during clashes. This jax can enter clashes right after tanks go in you cant fight all of them at ones. In the items build you can see I added Phantom dancer in the item build which others think that its a little off build. But it is an assassin jax with killer attack speed and can use the passive effects of relentless assault multiple times.

Assassin jax are best on fighting tank types who cant be beaten on simply attack or magic but assassin jax delivers both so thornmail can do any effect bec of some ap on jax and lifesteal. force of nature can be beaten by its massive attack damage and agility.
Assassin jax can easily move through clashes because assassin jax is made to secretly kill enemy in clashes and kill slow mages and soft assassins. Assassin jax can catch up to any fast moving enemies with its fast movement speed and leaps. Assassin jax can go head to head with any strong fighters and mages without sacrificing much of its health. It can kill an enemy within seconds. If faced with an ap jax Assassin Jax can fight without waiting for skills to cool down combined with red buffs assassin jax is unstoppable.
Its disadvantage is when faced with multiple enemies with multiple stuns. Assassin jax can go into a clash 1st bec he will be noticed 1st. in battles using this build you must have atleast 1 sure tank member or assassin jax will be killed 1st in clashes. tank is used for distraction and jax is used to kill the distracted :)