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A question born from a dispute in a Tabletop Game.

  1. May 7, 2014 #1
    Howdy, all!

    So recently I got into disputes with players about a situation that occurred in a tabletop game we are playing. I won't bore you with the details but it boils down to this:

    The effectiveness of an empty, wooden sheath in penetrating and impaling the human heart.

    A bit of additional information:

    1: The sheath belongs to a 6" Kaiken, a Japanese type of dagger commonly used by feudal era women for self defense, and is unmodified except for the blade having been removed and a wooden tab being used to keep the grip and the sheath together. The sheath has a dull flat butt as it the norm with Japanese sheaths.

    2: I found information saying that the breaking point of ribs are 150lbs/in^2, is this true and applicable for this situation?

    3: Assume the possibility of superhuman strength.

    Their argument is split with them saying that anything can become a weapon with high enough stats and my argument is that the forces used would break the weapon before it accomplishes the goal. I want hard evidence to put an end to this.
  2. jcsd
  3. May 7, 2014 #2


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    Well, even if it does break, there's a very real possibility of it splintering and then acting as a knife and stabbing in between the ribs.
  4. May 7, 2014 #3
    If superhuman strength is permissible then superhuman speed should also be permissible.

    Consider the blunt end of the sheath as a simple projectile, at a certain speed it will have enough momentum to penetrate the sternum whether the rest of the sheath is behind it or not. At that point the structural strength of the sheath becomes irrelevant.

    You can find pictures of hurricane damage where boards have been driven through concrete barriers illustrating this principal.
  5. May 7, 2014 #4
    Perhaps. However, you have to remember that the wooden sheath specified is only 6 inches long. If gripping just the sheath with an effective grip, this would leave only three inches of possible impalement with a single thrust if you assume that no length is lost in the splintering process.

    Then you have to take into account the spacing of the ribs, known as the intercostal space. The widest amount of space are in the areas where the lungs are, so you have to take that into account. Closest to the heart the space is very narrow, a rather useful formation to protect the heart.

    If you want to try an go under the heart, you have to then take into account the thickness of the ab muscles then. While not as strong as bone, they offer an effective barrier nonetheless.
  6. May 7, 2014 #5
    That.. is a very fair point. None of them spoken of the enhancement of to speed, only to strength. (In the game, enhancing speed and strength are two separate abilities. They only spoke of the strength enhancement.)
  7. May 8, 2014 #6


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    But in physics higher force means more acceleration resulting in higher speed. If the game rules are not consistent with normal physics, then what's the point asking here about normal physics. Play according to the game rules.
  8. May 8, 2014 #7
    I actually brought it up to them, they explained that the ability that 'enhances speed' is better explained as the ability to move faster from point A to point B, not the ability to move your body faster. In other words, it isn't applicable in this situation.
  9. May 8, 2014 #8


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    I still don't know, why you post this in a physics forum. But here is a hint: People play chess for ages, because it has simple rules. So you spent your time playing, not arguing about interpretations of rules.
  10. May 8, 2014 #9
    The rules don't cover this though. Tabletop games are entirely made up of interpretations.
  11. May 8, 2014 #10
    Isn't there a game master like in D&D to decide that?
  12. May 8, 2014 #11
    Here are a few things to think about.
    Instead of a simple stab a person could place the point of the sheath on the skin and steady it with one hand and then use a hammer blow or open palm strike to the butt of the sheath and then the full 6 inches can be used.
    I cannot remember if it is between ribs 3 and 4 or maybe 4 and 5 but if you stab at approximately a 45 degree angle upwards between the ribs then it is virtually impossible to miss the heart.
    Also the sheath could damage the vagus nerve instead of the heart and then the person could die of heat failure or asphyxia.

    One thing that is most important is this, Are you the GM or a player? From your posts it sounds like GM. The second thing is this, is the world a fantasy world or a real life analog? Also in the rest of the game how strict has the GM been about obeying the rules of physics?

    I see a few ways to resolve this.
    I have played RPG's for more than 20 years so I have some experience in this.
    1.Decide how important to the game the answer to this question is. If it is not very important then you may want to let it go and save putting your foot down for another time. However if this is very important or campaign altering for the worse then remember you are always within your rights as GM to just say it doesn't work.
    2.If this is a world with magic then tel the group you will roll to see if they were able to do it and then if they are able tell them that when the sheath touched the heart the sheath rebounded out of the wound with tremendous force. You can if you want explain that the person they are attacking that way has had high level magic put on him/her that puts a repelling ward around the heart so that the person is protected from instant death. Perhaps you can decide that this ward only works a certain number of times so the party knows that they took down part of the protection.
    3.If this is a real world analog then you can rule that the attack went in but that one of the ribs was hit and caused the strike to go awry. This is eminently reasonable especially if you tell them ok and you roll the dice several times to let them think you are checking to see if it works.

    I have other ideas if you want to message me with more specifics.

  13. May 9, 2014 #12
    Ah, but this is a Kaiken which has a flat round sheath butt, not a point. Thus there is no means to focus the force of the impact onto a space small enough to break through the resistance of the skin.

    Also, the game uses one part real world and one part fantasy. It's the New World of Darkness which adds Vampires, Werewolves, Mages, Changelings and a whole bunch more into the real world. For some reason it was decided that most of the Vampires are hyper paranoid about things like wood and fire. For me, personally, there is a difference between a toothpick and a length of sharpened wood launched from a crossbow.

    Note: I said SHARPENED wood. I still can't believe a blunt piece of wood can do the function. The force required to punch through skin, fat, muscles bones and organs to reach the heart would break the sheath first. In my opinion.

    Also, I'm a player and discussed this with other players. We never got a ST involved.
  14. May 9, 2014 #13


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    It can, just more painfully.
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