I'm trying to complete all missions without civilian deaths, so I have to skip poisoning attempt. But each time he sees me, he pulls out the sword =/ What I'm doing wrong?(Tzun hasnt notice me, I'm able to sneak past him at least.)

I have made like a billion attempts to beat that mission since the game was published in 2000. Unfortunately the best way to do it I know is to grab an AK47 with lots of ammo and kevlar armor (both can be obtained in the guards' quarters) and massacre everyone in Lee Hong's HQ and then go upstairs and kill him. The bad thing is that afterwards you will have to return to the restaurant to deliver the jade figure and you can only get there by using the sewers but normally no guards outside the HQ should see through your disguise, despite the shoot-out.

Yeah, thats pretty much what I did, but since some people are able to knife/wire Hong, I gues you are supposed to be able to do that. But is he supposed to be able to notice you? Does he stop noticing you if you try to poison him?

Of course, it might be that I didn't know how to sneak when I tried to do the mission :P

Now I*m trying to kill Pablo and blow up his lab.

I believe the only time I managed to strangle Hong was after the poison attempt. I ran after him when he tried to return to the HQ and grabbed him on the way. I never managed to kill him silently in his HQ though, he always seems to spot and attack you with his sword - maybe the only disguise he won't see through would be a civilian's and that's not an option for me either. And even if it actually is possible to kill him silently, it's so risky, that I prefer clearing his HQ in advance.

I guess you just have to sneak in his room, hope he doesn't see you and wire/knife him? .-. Almost all walkthroughs say that they used knife/wired him, but they don't really get detail into his ability to detect you. That or I read them badly.

the cleanest way is probably sniping him from the kitchen. that's how I usually do it. you need to get your timings right (and avoid poisoning the food), but it's not that hard.

Uh. But ONLY way to get to him in first place IS wearing triad uniform as otherwise you aren't let in... Anyway, point is that as soon as he saw me, he attacked me with the sword. I wonder if that stops happening only if you have tried to poison him...

Nah, I just avoid killing civilians and kills that costs you.

Also I completed the mission already.

Yeah, since he saw you being created by Dr. Ort Meyer, he's able to recognize you as an assassin.

not sure how helpful this is, but in my case I went through with the poisoning. then I changed back into Triad clothing, went into the compound via underground.
when I got to his office, he was pacing non-stop. So i just timed it to insure to stay out of his line of sight, then snuck upon him in the one cubicle that has no guards, and used the piano wire. The guards went on alert once his body collapsed in their line of sight, but none started shooting me, and I was able to walk down to the boat.

It's also possible to snipe Lee Hong while he's in his mansion. You need to take the sniper rifle to the garden overlooking the mansion and shoot him from there.

No matter what you do, though, this mission can be a pain and you will eventually have to go underground anyways.

For example, if you get the Jade statue first and give it to the old man, Lee Hong will come out of his mansion and if u kill him or his bodyguard, chances are that the mansion will go on lockdown.

If you kill Lee Hong first and get the Jade figurine later, the mansion will go on lockdown and you will need to go through the underground passages to get back in to escape.
It's really badly designed that way.

You'd get this if you watched some Youtube videos but to kill Hong without poison the best way if to shoot him through the window from above on the roof and then switch uniforms so you can just walk out(I'd suggest killing your uniform change before you take out Hong to expedite your departure from the roof. Once down they won't take you out.).

Hi :)

Here is my method,how to kill Lee Hong,when you got everything and bring Jade figurine,to Herbal/Wise man,he,ll give a poison,now you can use poison to spice up the Lee Hong soup or you try this,move yourself to the right door corner and open the door,you,ll see Lee Hong and his bodyguard Tzun,wall towards the table,prepare your silent gun and kill Lee Hong (all guards has to be in other places-Garden era....),wait a few seconds in Herbal shop,and then move to Garden era,if you lucky you will see Tzun walking towards to Lee Hong Manison house,follow him but keep the distance beetween Agent 47 and Tzun,enter to Manison house,find the elevator and escape with the boat.