Old Hari-sama speaks. Minoru. Fuma. Jinsei. Kaida. I have know you and watched you all since you were babies. You have been earnest students, worked very hard, done well in your training. I have seen all of you cry tears from exhaustion, physical pain, and pure, well-justified terror. You have done well, as we expected. You are now given a chance to repay the clan for the food, clothing, shelter and safety it has provided you from infancy to now. And a chance to provide the same for the ones younger than you, and the elderly too. You will not fail at what you are about to be told to do. He stops speaking.
Gosenkugi, the middle-age woman called Spike, says There is a merchant in Kofu named Tanaka Jiro. He specializes in buying and selling vegetable oil. For cooking, lamps, herbal tinctures, soaps and any kind of lubrication. He has grown quite wealthy, possibly because the war and the Takeda buying so many provisions and arms at high prices. He has grown wealthy enough that he has sought to rise in station by buying the Kofu summer villa of an impoverished noble of Kyoto. It's said to be in some disrepair, and that during the noble's ownership of it, a servant girl took her life in it. Jiro has a hook nose, which is quite a distinctive feature. Spike-sama holds a crooked finger beside her nose to provide a visual memory point. This Tanaka has been accused of mixing cheap animal grease into his oil, in violation of Buddhist law against killing and Shinto horror of contamination and pollution. It seems that he is not well-liked, even by his fellow merchants. Or especially not by them.
But the merchant is not the objective. The objective is a teacup. A humble enough sounding object. But this is one crafted by a late master ceramistist and Zen painter named Noritake. A unique work of art, and extremely valuable. And it is somewhere in Jiro's villa. We have been contracted to find the cup and retrieve it. That's all, plain and simple. You are given background information about the merchant's daily habits as a backup, so that you may have full information about what is known of the target. It shouldn't need to be said that the information is for making a well-considered plan for operations. And as information on how to plan a secondary operation, in case the first should fail."
It also goes without saying that the cup must be delivered intact. Unbroken from the blow of weapon, a fall, or any other mistake while on a mission-- and during the crucial successful return from it. She pauses a moment. If you fail and are captured, your throat must not breathe breath for your mouth make words. This also goes without saying. You have graduated from training and are now selected for a mission for the clan. The woman eyes penentrate the young ninjas' own with seriousness. But not unkindly.
Short, slight and stern Tsubasa-sama does not hesitate. "Now you know the objective. Time for the logistics of it." He unrolls two ink-painted maps. He jabs a finger onto one of them. This is the Mura ("The Village"). This is Kofu.
He indicates a spot on the other map. The merchant's villa is here in Kofu.
"It isdistinguishable from an ordinary rich man's house because it is built in the shinden zukuri style of the nobles of Kyoto. In that style, two long open galleries lie alongside the courtyard garden. From them guests view performances, or view cherry blossom or the the Moon and compose haiku. There are other mansions in that district of Kai, but no other is built in the shinden zukuri style. Make sure you investigate the correct location, and no other.'
Next, your route to Kai. There is the mountain route, which is shorter, and good in the warmer months such as now, when there is little chance of being trapped by a snowstorm. But it is a wilderness route, and home to the beings of wild places. The river route is safer, and passable in winter. But it passes along human farmhouses and settlements. If you go this way, you must pose as peasants taking goods to the market. The clan would provide you with vegetables, dried fish, wild herbs, or firewood for this. To be thorough, you would have to vend the goods, and purchase common items that a mountain village would need-- salt, tea, iron pots, tools, fish hooks, and the like. We would provide a list of items the village actually needs. And some red herrings.
You should expect the merchant to have some ronin guards. Perhaps two to three of them, probably all bushi, but not necessarily. Armor is in high demand and expensive because of the war, and the Takeda clan of Kofu prohibit non-Takeda from wearing armor in the city. We wouldn't expect the ronin to be heavily armored. But the merchant Tanaka Jiro is wealthy, and money often makes exceptions to rules.
Old Needle-sama speaks again. Now, the kami will decide which of you must take the role and responsibility of the Rooster. The agent charged with deciding for the group, when there is no time or opportunity to discuss. And charged with the responsibility of saying when the mission cannot succeed and it must be aborted. And... with mercifully erasing a comrade who may be captured and cannot return. Kawaishi-sensei brings a small woven bamboo basket. Inside are three black stones and one white from a Go board. Draw one each. The drawer of the white stone must of course be the Rooster.
1 - Minoru
2 - Fuma
3 - Jinsei
4 - Kaida
[1d4]=1
Minoru, the gods have chosen you today. All of you, plan well, execute well, achieve the objective and successfully and safely return.
I realize that you're still finalizing characters, but I thought knowing initially what to expect might help with that.
You'll need to decide on your route to Kofu. The river way is 17 miles, over the mountain is 10 miles, but rougher terrain. And if you want, you can discuss what roles your PCs will take in the mission, and generally how you want to do it. The Rooster isn't exactly the captain of the team. He's the tie-breaker when the team can't decide what's next, and as was said, he's responsible for calling off hopeless missons.
Please feel free to ask GM questions about what to expect of the villa's layout, interior, lighting, inhabitants, etc. Bushido's Nippon has some general Japanese culture expectations, so your PC's would have that information.
She could only take one Ninja skill and Jemmus said she would need Ninjutsu and not Hensu-jutsu the first mission... 
