Preparations

Our story opens in the morning, in the village of Sternvale. Werner Coates, a wizards' college grad student (though one with no magical aptitude), is planning an expedition to a nearby monastery to investigate their library for any valuable information that might help with his thesis. Responding to a budding scholar's request, three adventurers meet him at the tavern...

• Elias Sloter, a travelling monk, is also interested in the library in the monastery, although further funds for his pilgrimage are by no means unwelcome. He brings a wealth of knowledge regarding exorcism and religious ritual, as well as the blessing of magical healing. 
• Miguel Gores is a down-on-his-luck mercenary stuck in this backwoods village until he pays off his gambling debts. He's looking for a quick payday and is willing to lend his sword arm - although his sword is currently being held as collateral. Besides, he can't just watch this kid walk to his death. 
• Lottie Hadsall, the village urchin, has been hearing tales about the valuables the monks left in the monastery as long as she's been alive - not very long, as it happens. She's happy to lend her skills at picking locks and creeping around, as long as she gets a decent cut. She's not much good in a fight, and has a habit of telling lies, but once she's been paid she'll stick around until the job is done. 

The unlikely party come to an agreement and separate for the day to collect their equipment. The monastery is about three hours' travel away, so they don't bother to prepare sleeping arrangements. If all goes well, they'll be back by bedtime. They're equipped as follows, some of which they owned beforehand, but some that they purchase for the adventure:

• Elias, being a travelling monk, has very little to his name - only 10 silvers in walking-around money. He arms himself with a decent quarterstaff, a sling, and a pouch containing 25 lead bullets and a half-dozen bandages. He uses his remaining money to buy a padded jerkin, a lantern and a pint of oil for it, and another pouch containing his personal basics and a day's rations. The whole lot fits on his belt, leaving him lightly encumbered, and with 2 silvers and 11 coppers to his name. He leaves the remaining ha'penny as an offering at a nearby shrine. 
• Miguel, having left his sword with the card sharks, is forced to go back to basics. He hangs a club and an axe on rings on his belt, as well as sticking his trusty long knife in his boot. He lugs a medium heavy shield on his back. He considers bringing his crossbow, but is assured that in the corridors of the monastery it will come to no use, so he leaves it behind. Suitably armed, he wears a heavy leather jerkin and boots, protecting his arms, legs and hands with lightly padded sleeves, leggings and gloves, respectively. He guards his head with a layer of padding, over which he pulls a mail coif. On his back he wears a small backpack containing his personal basics, a day's worth of rations, a 10-yard coil of 3/8" rope, a first aid kit, and a folded sack (for looting). This leaves him at just under medium encumbrance. He chooses to pocket the remaining 4 silvers and 9 coppers, just in case. 
• Lottie has scrounged together a fair bit of cash over the years - she has more available to her than Elias, but not as much as Miguel or Werner. She buys a pouch containing a set of good lockpicks and a length of cord, and hangs it on her belt next to a long knife. She buys a pair of heavy leather boots and sneaks a small throwing knife into the right one. To prevent her from bumping her head in small spaces, she buys a light padded cap, and a pair of heavily padded gloves, just in case there are any pointy things hidden away in tight spaces where she puts her precious fingers. The remaining nine coppers are slipped into the pouch, leaving her well under light encumbrance. 
• The leader, or at least patron, of the party, Werner, purchases a quarterstaff, a heavy cloak, and a long knife, although his experience with using them in combat is nominal at best. He buys a light mail vest to hide under his shirt and a pair of good boots. Suspecting danger awaits, he purchases one book on Poisons, and spends the day poring over the tome to put it in one of his Book-Learned Wisdom slots. He spends one copper on two tallow candles, and buys a small purse to put the remainder of his money - 6 silvers, 12 coppers - in. The load puts him into light encumbrance, and his hands are full, but what are the odds that they'll be attacked before he has a chance to put his book down?

Commentary: what's with the long knives?

Why do three out of four of the characters presented carry long knives? Well, when the Basic Set of GURPS 4th Edition came out 20 years ago, the spectrum of one-handed bladed options was pretty short. Ignoring fencing weapons for now, you had: 

• Small knives (and their oddly named thrusting-only counterpart, the dagger), which can only be used within kissing distance, and did anaemic damage, but were easy to learn, at the cost of being hard to parry with;
• Large knives, which dealt a little more damage and straddled the reach line - you can use them at arm's length and in close combat, making them pretty much your only option in a fluid melee with grappley types;
• Shortswords, which are just a little too long for use inside your personal space bubble - once they're in there, you might as well not have it. Not to mention, for the same skill cost you're less proficient than with a knife, but at least you don't take a penalty to parrying;
• Broadswords, which have exactly the same range as shortswords, but do more damage. Uh, yeah. 
• Bastard swords, which can be used at both arm's length and the next space over to slash, but only to stab at a distance. They're also unbalanced when used in one hand (so you can't attack and parry on the same turn). Obviously, the bastard bit means if you're willing to double up on skills you can use it in two hands to eke a bit more damage out, making it a little more attractive, but losing the opportunity to use a shield is a hard sell. 

In practice, this meant your options were large knife, broadsword or bastard sword. Shields penalise close combat, so in a mixed brawl - which is what all fights descend into - a broadsword in hand and a large knife at your belt was the way to go. When the Low-Tech book came out six years later (in 2010), it added a tonne of cool weapons, but relevant to this discussion are: 

• Long knives, which can be used to stab and to slash in close combat and at arm's length, suffer no penalty to parrying, are less than a third the price of a shortsword, and deal more damage than the large knife, while being easy to learn;
• Longswords, which are like a broadsword with the added option to stab an extra yard over. They're not even unbalanced! Like a bastard sword, you can two-hand them for extra stabbing power, although they don't slash quite as good. 

Clearly someone saw that the shortsword was the red-headed stepchild of this arrangement and threw it a bone in the form of a little extra thrusting damage, so now it sits smack-dab in the middle between long knife damage and broadsword damage. Unfortunately, this doesn't fix the reason why the shortsword never gets a second look. Sure, damage bonuses are important when you aren't very strong - it really sucks to roll 1d6 and have your stab bounce off half the time. But once you get to two dice worth of damage, whether it's 2d6-1 or 2d6 is pretty much academic, and every fighter worth his salt is swinging for at least 2d, probably 3d if they're dedicated to whacking things. So your options are primarily limited by reach. And the shortsword can't be used in close combat - and it's necessarily worse than a big-boy sword in a stand-up fight.

Basically, the long knife hits all the breakpoints you want for a backup weapon, and if your character isn't wearing one, he must be wearing suspenders, because there is one on every belt.