What would you make the rarity of a koku requisition? Like “hey boss can I have 10 koku?”

Depends how well off the boss is. But I'd probably consider it in the order of 6 or so. Broadly speaking, if you can requisition gear worth that much, the money can be about the same value.

There will be exceptions; if you're at a fortress at the wall, weapons and armour to suit up for a battle are stocked en masse in the armoury but money is hardly there in droves, whilst the Black Crane Estates is one of the biggest trading centres in Rokugan so a lord based there would probably rather hand you the gold and let you equip yourself rather than trouble their own storemasters.

14 hours ago, AndyDay303 said:

What would you make the rarity of a koku requisition? Like “hey boss can I have 10 koku?”

I'd probably check the item price list and go with that. Maybe adjust difficulty based on the starting koku for the family.

Lookoing at the listo 10 koku correspond to the prices of the Trident, the Naginata and the Yurt so rarity 5-8. I think 5 would be a good starting point and then adjust by 1 up of for every time it halved our doubled the family starting koku.

Then again I would be tempted to just have the Daimyo go "Do I look like a scummy moneylender to you? Are you implying the stipend we provide you is not appropriate for your duties?".

41 minutes ago, Suzume Chikahisa said:

Then again I would be tempted to just have the Daimyo go "Do I look like a scummy moneylender to you? Are you implying the stipend we provide you is not appropriate for your duties?".

There’s a limit to how much I’m willing to turn a requisition attempt into a role playing moment. Methinks.

The Moto lord narrowed his eyes at the young shugenja kneeling before him.

"Khujaji, you have a fine horse. A skin of water. A travel pack with everything you need to survive. And your honor tucked into your obi. What need have you of..." His face nearly sneered in disgust as the word passed his lips. "Money?"

"Moto-ue, if it pleases you. I am traveling to Otosan Uchi in my new role as an Emerald Magistrate. And I am traveling with a Scorpion."

The daiyamo laughed and rose to his feet. "Well, in that case Khujaji-san, you will get two purses. One scant with koku to show your stinging friend, and one with some real coinage to never show him."

"It's a barter system" is an argument that only goes so far.
Our (modern, capital-based) economy is also a barter system - the only reason a dollar holds any value is because you can pay your taxes with it. If you couldn't, it's value would vanish entirely. Since every single transaction you make in your life can't literally be a barter, the mint steps in and substitutes for the good and/or service.
Koku/Bu/Zeni works in much the same way for Rokugan.

I also think, "the clan will provide your needs" argument is veeeery overplayed (even by the developers, IMO).
Yes, the clan provides for you in the form of food, shelter, the necessary items to fulfill your duties (daisho for samurai, etc) but that's the beginning and end of it.
Your lord could have provided you with much better quality armor, and you'd be much safer and more likely to survive and succeed at your tasks, but they didn't - you got what you got and if you want better, it's up to you to remedy that (whether it be through crafting, bartering, politicing, purchasing, etc.) This is the part of the game where some economics belongs, but is sort of missing.

It's also kind of important to remember that the nobility gets a stipend but not everyone does:
Peasants live entirely off the land; their place is to feed the empire and in return they are allowed to live on the Emperor's land under their protection, but they get no quality of life that they cannot make for themselves. What they do, however, is produce and sell the day-to-day materials that are necessary for essentially everyone. linen, woodworking, leather, silks, etc and any/all of the basic things you may need these for (ricepaper patches for broken doors, silk thongs for straps, paper lanterns, hand fans, pouches, clothing, etc and so on and on).
Merchants are simply peasants who have managed to make quite a quality of life for themselves (peasants who have been lucrative enough to "move up" out of the farming life and into the trading life or who provide a service that is important enough to keep them busy even during harvest; a sword polisher for instance). It's worth noting that very successful merchants tend to have more koku than many samurai and it's for this reason they're allowed into the politics game at all, but their wealth is entirely all they have since they are guaranteed nothing through their class (as a samurai is with their stipend).
Next come samurai, which bucks the trend and is given generally what they need through their stipend, but still will expect to have day to day expenses and these expenses are paid in koku, generally to peasants and merchants in town markets. Want to paint a beautiful fan as a gift for an upcoming visit to a neighboring lord or court? Making the fan is up to the samurai but crafting the paper, wooden ends, pins, inks, etc is not something samurai are doing, they'll pick these items up with currency.

Now obviously the game doesn't expect you to be taking time to select which quality of sandal strap you want to purchase with your money, and anything like that should be either hand-waived or done entirely narratively, but this is where we get back to "your lord provides (but not always)." Your family armor is damaged but not destroyed. You wouldn't requisition new armor to replace it (it's your family armor, not some throw-away gear you got out of a barracks surplus) but it still needs repairing, and your stipend is meant to cover expenses like this - except there is no stipend and your starting money is veeery finite when we start dealing with the cost of actual items of consequence (weapons, armor, horses, etc).
Or, going an entirely different way narratively - your sword is broken in combat and instead of replacing it, you are shamed for allowing it to be destroyed in the first place. After all, it is your duty to care for your equipment properly and any samurai who allows their (sacred) katana to come to such harm is neglectful, a terrible swordsman, or both (ie: your lord is a cheapskate and will play politics to line their own pockets). You can't craft your own without essentially removing yourself from the game, and your starting funds won't cover a katana - what do you do?

Well, as things are, the answer to "what do you do?" is either a) ignore this type of narrative entirely and never have it come up, or b) rewrite the way koku works which is a ton of extra world-building that, technically, should already exist.

I can't remember if "way of the daimyo" had anything of value to add to the conversation (on managing wealth, taxes, and construction), but I remember borrowing some ideas for a 3rd or 4th edition campaign many years ago if only to help define a few more things behind the curtain.

That said, I've fallen into the same developer trap? convenience? where even if the PCs aren't personally conducting dishonorable trade, all of their "purchases" in town are recorded off camera in a ledger to be delivered to their respective masters. If the goods and services are within their station, there isn't a talking to later on, and the story continues. If they are requesting too much, the point of sale politely refuses not wanting to personally invoke the ire of their master.