Well. I went and saw "The Last Samurai" movie before starting this, looking for some possible motivation.

I must say. Hollywood has never hesitated rewriting the U.S.'s culture and history to suite its dramatic needs. But it just seems violently insulting when they do the same to other cultures. Entertaining it was. Accurate is was most definitely not.
Diplo update: We are at war with the Date, Takeda, Ichijo, Shimazu, and Matsunaga. We are only committed to Alliances against the Takeda. 2 turns until we learn Bushido,
(I) Otomo and Ichijo MA against Tokugawa. Shimazu declare on the Imagawa. Otomo and Oda MA against the Ihcijo. Some enemy figthing on our Eastern Borders.
Jul, 1532 (1) I swear. If we had any more ships in our territorial waters, there would be gridlock!

Ask Chosakopi units to leave, and they do. Ask Saito units to leave and they do (they were sitting on our main road!). Make peace with the Date for 60 gold. I could make peace with the Matsunaga, but we might be beating up on them next. Healing turn.
(I) 3 Matsunaga ships drop off a single horseman near Yonago. Chosokabe and Oda MA against Imagawa and the Ichijo. (Great news - the Chosokabe are on the same island as the Ichijo, so they will have much better things to do then amphibious assault us.) Shimazu declare on the Oda. Our Golden Age ends.
Oct, 1532 (2) Cleanup Matsu horsie. Check to see if anyone else will talk peace - No. Maizuru now connected by road. Advance our spearman Line of Defense Eastwards. Our stack moving towards Nara rolls onward.
(I) See our allies-the Matsunagas- tear apart a Takeda stack on our border. Date declares on Tokugawa. Chosokabe and Oda MA against the Date.
Jan, 1533 (3) Spread out some more defenses in the South. Settler activated to claim some land. Spear wall starts fortifying on a new line.
(I) Hojo and Chosokabe MA against Date. (Doesn't anyone ever make peace?) We decline a MA offer from the Chosokabe. They do a MA with Shimazu against the Hojo instead. The Takeda offer peace which we decline (They have 9500 gold!

) We repel two of their Sam Archer attacks on our stack.
Apr, 1533 (4) We learn Bushido and start on Bajutsu. Decline the "U.N." vote (We could win that without any sweat because all the other Civs have screwed their reps many, many times over!) Start Sam. Warriors in many cities (7,7,1) Keep research at 90% for Bajutsu (Mounted Sam. Warriors seem to be the way to go.) Den of Spies costs 400 shields? Sheesh! 3 more turns to go on that. On second thought I change our research to minimum to save money, and will try to steal Bajutsu instead. Make peace with Shimazu for all their gold. Ichijo are still not talking to us. I shop around to see if we could sell Bajutsu, but the laggards have no money.
(I) Saito and Takeda sign peace. Matsunaga declare on Otomo. Lots of fighting near Nara. Imagawa and Hojo MA against Date. Matsunaga and Hojo MA against Date. Imagawa and Uesugi MA against Matsunaga.
Jul 1533 (5) Found Masuda on ruins of another city. Our stack is next to Mara now. Bombard and destroy a small Takeda stack outside of Mara. We're going to need more units. Takeda units are swarming everywhere.
(I) Alright. I'm giving up anouncing all the alliances during the interturns unless they involve us. Just assume there are at least 3-5 of them and you'll be spot on. 3 Takeda ships drop off a 7.7.1 Sam Warrior near Hirata.
Oct 1533 (6) A bit of RNG luck leads to a Ninja victory over the Sam Warrior. Still bombarding the stacks around Nara.
(I) The usual.
Jan 1534 (7) Den of Spies finally completes in Hiroshima. Plant a spy successfully with the Tokugawa and manage a safe steal of Bajutsu first try! We enter the new age with a single straight tech tree and start on Akinai. All build orders changed to Samurai Mounted (7.7.2) and a few Horse Archers sprinkled in. Bombard and kill 4 Takeda units near Mara. Sell some old techs to the laggards for some small amount of cash. Make peace with the Ichijo straight across. Make peace with the Matsunaga for all their gold and 15 gpt. (The Takeda are not going away anytime soon!)
(I) Some actual peace treaties happen. (Unbelievable!) Of course, 3 treaties and 3 MA's net out to zero, really.
Apr, 1534 (8) Our first Mounted Samurai appears and charges towards the front.

The units near Mara are continuing to bombard and pick off Takeda units. Ninja units sure are fun to attack with since they can select any target in a stack! Tip - you can instantly see what you are facing in a city battle by having a Ninja attack, then declining to make a selection of the unit. Instant intelligence report!

Upgrade our Leader to Shogun 8.
(I) The parade of boats on our coastline should be converted to a tourist attraction.
Jul, 1534 (9) Uhmmm...more bombardment, 3 more Takeda units killed.
(I) What the ???? Is every unit amphibious? The Takeda attack Kasuga with 3 Samurai Archers from ships. We defend OK, and then they dump 2 Yamabushis and 2 Sam Archers on a hill nearby.
Oct, 1534 (10) We would have been in trouble a few turns ago with this invasion, but now we have a steady stream of Samurai Warriors and Mounted Samurai wandering by. They eliminate the invaders with no losses. We manage a safe steal of Akinai from the Tokugawa. Contact with Portuguese is next. Trade around some techs to the laggards, and gain some good money. During the usual attack on Nara, a Ninja generates a Great Leader! (Ankokuji Ekei)
What do you want to do with him? (My vote is for Mounted Sam. Army)
We are now nearly caught up on techs. Sorry for no cities conquered, but we did gain some territory and didn't lose many units, and have only one enemy now. The same warning that Lee had holds true - don't let a hole in our Spearman line open up or else those Yamabushis (Who put Conquistadors to shame!) will invade in less than a split second. With all these amphibious units around, we might consider putting 3 good defenders in our Coastal cities eventually.
The Game (Oct, 1534)
For anyone who still doesn't believe the rapaciousness of the Yamabushis - check out the picture below that used to be the heartland of the Miyoshi. As you can see, developed squares are pretty darn scarce!