Koi Clan

Description
Koi's ability allows for them to use their coin as Ronin, making them a formidable military opponent that excels at the Ronin Strategy.

At the start of the war phase, Koi converts all Ronin tokens to additional coin. Next, to use their ability, Koi need to win the Hire Ronin action during a battle, which will require them to pay a certain amount of their coins. The remainder of their coins can then be used as Ronin tokens, effectively adding to Koi's force during the battle.

The coins that were spent on winning the Hire Ronin action does not count as Ronin during the battle, and will be either removed (if Koi loses) or distributed among the losers (if Koi wins) when the battle is resolved. The coins that were used as Ronin remain with Koi and can be used again next battle as regular coins.

Strategy
Koi clan's ability heavily depends on coins, so cards or Kami that offer money and Ronin are often the best choice for Koi, as being the richest player on the table typically benefits Koi as they are very effective at the Ronin Strategy. A basic Koi strategy therefore revolves around the following principles : Aside from Season Cards that provide a steady income, Koi should also look at alternative options such as: An early alliance with the clan that comes after them benefits Koi, as this will typically get them good position on the board and more alliance bonuses in the first Season as a 1-2 alliance gets to play the maximum possible amount of mandates, regardless of the player count. In a 3 or 4 player game, a 1-3 alliance could be even more interesting as the 3rd player resolves a mandate before the first Kami phase.
 * Koi should aggressively go after War Province Tokens and try to win at least 7 different ones for the 30 VP bonus at the end of the game.
 * Koi needs to be careful spending too much during the Mandate Phase, as it relies on having a lot of coins during the War Phase to be effective.
 * Train mandates are very effective to Koi as their ability works particularly well with War Upgrades that provide coins or Ronin.
 * Kami shrines such as Tsukuyomi (for 2 coins) and to a lesser extent Hachiman (for 2 Ronin) - Acquiring Komainu can help Koi to keep control of them, but Koi can typically rely on ties and high Honor to eliminate the need for it.
 * Harvest mandates - Getting harvest in provinces that award Ronin and coin can be helpful to Koi, especially after clearing out these provinces by winning battles in previous seasons. Kotahi can be helpful to a Koi player to pick up Harvest rewards but Koi should prioritize cards that offer guaranteed income instead.
 * The Take Hostage action - Taking hostages is the only way to "keep" a coin from one season to the next, and it can be a great way for a successful Koi player with a lot of coins to transfer some of their wealth to the next season.

As Koi is typically an imposing clan with a lot of expected Force, they should consider to also use their Force as leverage in negotiation.

While Koi starts with high Honor and is built for the Ronin Strategy, it is not the only path to victory for them and a Koi player with a solid financial engine can surprise players by running a Big Force Strategy as well. As BoardGameGeek user Estoyldian explained, "A low Honor Koi clan with a couple of Onis in tow can make them even more formidable on the battlefield, increasing their overall Force and making War Advantages even tougher for opponents to bid on. The choice between Take Hostage and Hire Ronin may cause opponents to take Seppuku and try to fight another day."

How do Koneko (Kickstarter Exclusive) and the Koi Clan interact?
Koneko: ‘When this is killed, gain 2 coins and 2 Ronin. Other players in this Province lose 2 coins and 2 Ronin.’ The Koi Clan turn their Ronin into coins at the start of the War Phase and may use their coins as Ronin during Battle. How do these interact?

There is nothing wrong with the rules as stated, in that the Koi Clan would gain 2 coins and 2 Ronin if their Koneko was killed. Their ability doesn’t stop them using the Ronin as part of their ‘Hire Ronin’, and it is perfectly compatible with their ‘Use coins as Ronin’ ability. If the Koi are on the other end of Koneko’s ability, they can lose 2 coins (if they have them) but if they have no Ronin they would ignore that bit. The Koi are not forced to discard extra coins for the Ronin discard, as their ability to use their coins as Ronin is optional. They also do not convert the newly required Ronin tokens into coins.