This build is only a basic guide you may change anything on this to suite the style of you play.
hope this guide help you as much as it does with me.

Throw your sword at the bigger minions to get health back. also use your sword to get last hits if the minion is out of reach. you can spam it cause you don't have any mana!!!
getting *W* 2nd allows you to be a little more aggressive during the early game as taunting an enemy can cause a first blood.

*Locket of the iron solari* is the best item to have because it puts a shield around my team members, sometimes i use my ulti then i use the item to give my team mate more of a chance to live.
you also probably saying why get the a.p. item. his shield gets greater by ability power. so even the tiniest bit of A.P. helps you win or loose
You can either choose ninja tabi or mercury's treads, mainly depends on who you are laneing against or who on the other team is fed.

if you team has no support champ you should get a *oracles extract* and kill any wards you see.

get soul shroud to reduce CD's and such to help out your team!

you mainly need quicksilver sash so you don't need cleanse

When u grab your *W* at level 2 you can start to be a little more aggressive and start getting into the enemy's face. if they are hurting you attack then until they are running away then taunt then so they either die or go back and heal giving you the advantage!!
also if your team mate u are allying with has low health use the *Q* on a strong minion (with out attacking him) so your team mate can heal up to out lane you opponents!

The main reason why i take clairvoyance cause you are not only a take but you also have another extremely important role as a support!!
teleport is to also support lanes that your in, or team mates in other lanes might need help.

but feel free to change any of these summoner spells as summoner spells are really just your own choice because everyone plays their own way.

the reason why i dont take heal or flash. 1. Shen has a dash so no need for flash. 2. don't need heal cause you get Locket of the iron solari which is so helpful.

reason why you don't need cleans is because you are getting quicksilver sash in the build. so please what every you do, do not bet cleans!!! as their is no need for such Summoner Spell.

When u grab your *W* at level 2 you can start to be a little more aggressive and start getting into the enemy's face. if they are hurting you attack then until they are running away then taunt then so they either die or go back and heal giving you the advantage!!
also if your team mate u are allying with has low health use the *Q* on a strong minion (with out attacking him) so your team mate can heal up to out lane you opponents!

Pros:

* you can be a little more aggressive early game and still me tanking.
* you not only tank but you also are supporting your team during fighting.
* the items such as Locket of the iron solari help at anytime during the battle making you a unbeatable member of the team.
* the summoner spells i have chosen are ones mainly for supporting your team throughout the hole game as they allow you to move quickly to places and to spot enemy's hiding in the bushes.
* AOE taunt. that makes him a great Tank!

Cons:

* sometimes you may have Locket of the iron solari on CD so someone on your team may loose a life
* you maybe to aggressive early game costing you a death
* you can not tank against a team who is fed like crazy, as their damage will be too much for you to tank.
* could use Stand United late and ally dies in 2.5 second, you wont be able to teleport and end up with not joining in fight.

Ki Strike
Damage increased to 10-112 (+10% bonus Health) from 10-95 (+8% bonus Health)
Cooldown is now reduced by 1.5 seconds whenever Shen attacks instead of 2 seconds when being attacked
Now grants Shen 10/20/30 energy when he Ki Strikes
Damage now scale correctly with all sources of bonus Health (% health runes, Juggernaut mastery)
Added a buff timer for Ki Strike's cooldown (like Ziggs' Short Fuse)

Vorpal Blade
Energy cost adjusted to 60 from 70/65/60/55/50
Damage adjusted to 60/105/150/195/240 (+0.6 ability power) from 70/105/140/175/210 (+0.75 ability power)
Heal effect changed to 6/10/14/18/22 (+2% of Shen's maximum Health) from 18/26/34/42/50
If Vorpal Blade deals the killing blow, it will now trigger 33% of the heal effect for Shen
Allied damaging spells can now trigger the heal effect, in addition to attacks (Vorpal Blade cannot trigger itself)

Feint
Feint duration increased to 3 seconds from 2.5
Energy cost reduced to 40 from 45
Shield amount adjusted to 70/120/170/220/270 (+0.6 ability power) from 50/100/150/200/250 (+0.75 ability power)
While Feint is active, Ki Strike’s cooldown reduction on hit is increased to 3 seconds from 1.5

Shadow Dash
Cooldown reduced to 10/9.5/9/8.5/8 seconds from 10
Energy cost increased to 120 from 120/115/110/105/100
Restores 40 energy per champion affected (rather than a flat 50 energy if you affect one)
Now deals 50/85/120/155/190 damage (+0.5 ability power) to Champions
Taunt duration adjusted to 1.5 seconds from 1/1.25/1.5/1.75/2
Shadow Dash now grants Shen 50% physical damage reduction from taunted targets

Stand United
Channel time increased to 3 seconds from 2.5
Shield duration reduced to 5 seconds from 7.5
Shield amount increased to 250/550/850 from 200/475/750

First of all Vorpal Blade very powerfull i will give you that. Especially in early-mid game. Its heal helps you to stay in also its beneficial for your lane partner. If your facing a very decent lane with aoe spells, brush campers etc... you cant save your partner with Feint. So its suitable to use a 2level , 2level 1level in early game. Throw a Vorpal Blade to a full HP minion or siege minion and hit it once. Dont hit before its effect fades. Dont push unnecesaryly. Ofcourse dont wait if you facing a champion :D

NOT: I came up with a lot people that have no idea about the life tap factor of Vorpal Blade. Observe your partner if they are not hiting Vorpal Blade marked target, tell them "you know you can regen HP if you attack the target i marked" believe me they will be surprised.

When To Level Vorpal Blade
For example you are laning vs Garen. He uses Decisive Strike. And quess what? now your silenced and cant escape from Judgment also cant use Feint. So what ? Level Vorpal Blade. You can use a 3level Vorpal Blade 1level Feint 1level Shadow Dash setup in a lane like this. Toss a Vorpal Blade when he rushes you and fight. You will out damage him with some armor. When his Judgment finishes, use Shadow Dash and hit a few more times. Go back and heal up with Vorpal Blade
You dont have a jungler but they have. Your in top lane its 1v2. Try to get a carry near you. You can zone your enemy with Vorpal Blade + Ki Strike. Deny him from exp. and never push. Dont use vorpal blade on minions. Dont make yourself vulnerable for a gang ( a wild Udyr appears ) Just let your partner to get ONLY last hits. Warn him if he is auto attacking. And ofcourse always buy Sight Wards and place them near baron, in bottom brushes, etc..
If you are able to harras your enemy Vorpal Blade without taking much damage feel free to level it. Camp in brush throw a Vorpal Blade and hit Ki Strike then use Shadow Dash to brush again. For example your lane partner is Ezreal and opponents are Ashe and Janna. Ezreal has insane damage output at early game. Just taunt Ashe. Toss a Vorpal Blade and hit Ki Strike. Meanwhile Ezreal will unleash his + + combo. This will deal tons of damage. Even Janna's Howling Gale and Eye Of The Storm wont be enough and quess what? Ashe just used her Flash so next time "An enemy has been slain"

These are the key points of Vorpal Blade i dont recommend leveling it besides these situations. Dont forget you are the tank no matter if its early/mid/late game.

While most of spells base damage increase 25-40 our sheild increases 50 per level. So lets see its uses in game with some spells.

Mostly use it against and little harrasing moves.

Akali tries to harras you with Mark of the Assassin
Ashe uses Volley
Caitlyn shots Piltover Peacemaker
Cho'Gath slams Rupture
Dr. Mundo Damn that Infected Cleaver
Ezreal and early OP Mystic Shot
Galio gazes you Resolute Smite
Gangplank wapa-changs you Parrrley ( Watch Me )
Kassadin fires a Null Sphere
Katarina is a b**** Bouncing Blade
Kayle is not an angel Reckoning
Kennen you little.. Thundering Shuriken
Lux so hard to avoid Lucent Singularity
Malphite rolling rock Seismic Shard
Malzahar void man Malefic Visions
Maokai save your allies from Sapling Toss
Nocturne black nigga Duskbringer
Nunu cold as Ice Blast
Olaf technoviking Undertow
Pantheon A baker ? Spear Shot
Rumble you also hate it dont you Flamespitter
Ryze any spell but -.-' Overload
Shaco really a demon jester Two-Shiv Poison
Sion cant block his full combo Cryptic Gaze
Talon care with these blades Rake
Teemo I hate you so much Blinding Dart
Tristana no comment Explosive Shot
Twisted Fate cards! cards everywhere Wild Cards
Urgot your so ugly Acid Hunter
Wukong give him some bananas Nimbus Strike
Xerath little range Arcanopulse
Zilean biggest troll ever Time Bomb

Also any other DoT (Damage Over Time) spell and ofcourse "lovely"

You can block one of these spells if you only press your W button. Level it and use it then use it again. You will lol so hard when Time Bomb hits you 6 damage.

even know in this build we are going to be both support and tank you still need to think of different situation e.g. tank a turret or save someone.

1) As a Tank

Your the initiator, facecheck brushes, dive turrets, start team fights etc
Whos the most durable guy, YOU, dont be afraid of going the heart of the enemy team
As a tank you HAVE TO lead your team. Make them follow you. Write, ping do whatever you want but take their attention. You must be the leader dont let anyone else do it.
Choose most deadly, dangerous target ( Brand Akali Caitlyn LeBlanc Master YiTalon Twitch) and distract them. Keep them away from your team.
Use smart. You can taunt 3-4 enemies if you find the true moment.
i will explain some true moments later
Always know your enemy. Nunu 's Absolute Zero or Malzahar 's Nether Grasp and channelings like that are very critical so make division of labour in your team about who will disable which channel in order to not waste all CC on a single champion.
Always be patience before using and aim for those channeling spells.
Master . Use it learn it, it has more uses then you think

2)As a Support

Help your AD,AP carries to farm safer
Its probably too cliché but yes BUY WARDS.Buy when you can and buy if necessary.
Of course buying wards is not enough, you have to place them. In brushes,near Dragon and Baron,Enemy Jungle Buffs. If enemy Blitzcrank , Sion , Garen camping in brush, place ward there and let them see it they will probably not do it even if they do you will know their exact place.
Or if you dont know where to place wards, you can simply ask your team they will ping to you dont worry.
You shouldnt get kills when there is a Graves, Tryndamere, Kassadin near you. They need gold more then you as we have Mercenary we will also get gold from it. Kill = Asist in terms of Takedown. But Win =! Lose In terms of Wins. Obvious right ? You cant win alone but a fed and smart Jax can do a lot.
Motivate your team, tell them they are doing fine, say your going to win this (ofcourse dont say it if its 3-20 after 15min but everything can change).

3)As a Lifesaver
Map awareness ! You must learn it. You have to say that if your ally is in danger or not whenever you checked minimap.
In laning phase of game use your Feint to interupt skill shots and certain spells. You can regenerate your HP faster dont forget we are not leveling Vorpal Blade. I will also explain its reason later.
Whenever an enemy doesnt appear in lane say Mia (Miss in action). Shut it out, write with caps lock, use retreat ping a few times. Do not say
" Evelynn is Mia go near your turret you idiot or dont cry when she kills you again."
This is just not nice.. But if you say
"Carefull guys Evelynn is Mia she is probably roaming try to place at your lane." They will thank you and trust your leadership later.
If they cant effort for Vision Ward, do it for them. ( this can be also a job for support )
Again and again buy these s. They can save your team members more then you think. "Buy a ward, Stop a gang, Save a life"

Please try to master as much as you can in this build, so you can be as fast and light (ninja) as Shen calls it <3.