Question: How should a GM role-play a torture scene for a PC?

In one of my games, one of my PCs will be captured by the enemy who wishes to get information from him, using... less than ethical methods.

Leaving whether or not the information is divulged to a dice throw seems a waste, but on the other hand, it's hard to force a player to give up info if he doesn't want to.

I'm playing an L5R campaign, with the L5R system.

Answer: 
And just for completeness sake, as nearly all answers here seem to address to the question "How can I avoid explicit torture scenes as a DM?"

If it is OK
===========

So after going through the metagame topic of "Is it OK?" (preferrably in advance), and if it is OK, you can role-play it in a nasty simulationist fashion.

Prepare for the session as usual: 

* [research the topic](https://skeptics.stackexchange.com/questions/4498/does-torture-work-well-as-an-interrogation-technique)
* print out some torture devices (in black and white) and maybe some mutilated human bodies
* play out the two concurrent processes of torture - the dialogue with the NPC, and enduring the actions of the NPC (torturer)
* don't start out by "I'll ask nicely", start with some pain in order to put the subject in a stressed state, where lying would be detectable
* tortured subjects usually get executed afterwords, if they hold no more information of interrest

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Leave the system at the background
==================================

> 
> but on the other hand, it's hard to force a player to give up info if he doesn't want to.
> 
> 
> 

```
- Just hold still while I am doing to you eye what just happened to your finger. 

```

This situation is intended to scare **both** the character and the player. The character ... well, this is clear. The player, because he/she knows that you, as a GM, stand up to what you declare, and his character is going to have that -5 on any ranged check ... forever (in a non-magic setting). 

*"Hold Still, I don't have good depth perception!"*

---

How to establish credibility
============================

Needless to say, however, don't mention the ranged penalty during role-playing the scene. "You will get -5 to ranged attacks, are you sure you don't tell him the truth". This kind of metagaming brakes immersion! **Role**-play, then, as an epilogue to the scene, summarize the mechanical repercussions of the scene. Doing this several times in different situations immediately establishes the "you, as a GM, stand up to what you declare", mentioned above. 

Of course, do this for beneficial scenes too: "That kiss from the elven princess boosts +1 permanent Dex bonus. And now for the chase scene."
The biggest issue I see with this is whether or not the players will be okay with it. I have learned the hard way that if you're going to be doing any kind of collaborative RPing at *all*, from torture to simple vignettes, you almost *need* to have what story gamers refer to as "the veil":

**If at any time you feel uncomfortable with an idea, a direction, or anything that is happening at a session, you have the right to say "let's draw a veil over that".** At that point, we will stop doing that. The ONLY questions which we can ask are:

* Whether or not it's okay to "fade to black" on a scene and discuss the consequences of it, or if we want to kind of delete the whole thing from the campaign.
* What, exactly, we are drawing the veil over.

And that's all. What you **cannot** ask is "why". The veil is not intended to start a debate but to make everyone comfortable with roleplay. Hopefully it will be used sparingly but it is in my personal experience that some of the worst gaming experiences I and others have had was when someone should have pulled the veil over something but did not (or, in my case, we didn't have the "veil" rule in place and the player did not realize that he had that power).

The veil can cover something as innocuous as a name (perhaps a player's dead wife shared the name of the witch you're using - again, it doesn't matter why) or as extreme as "guys, let's draw the veil over torture".

I realize that you're asking for mechanics here, but I think that ultimately with a topic as contentious as this, this is a more important factor than pure mechanics.