Merchant skills present knowledge of certain practices that are not the domain of the samurai. While it is not inherently dishonorable to practice these Skills, it is somewhat questionable, and those who do so openly and regularly are looked upon with mild disdain by their more sophisticated kinsmen.
Rokugan has a vast coastline, and there is a tremendous amount of activity on the sea during the majority of the year. Trade vessels and fishing vessels make their way across the shallow waters along the coast during spring, summer, and fall, and the hardier ships belonging to the Mantis Clan make the long voyage to and from the Islands of Silk and Spice even during the depths of winter.
Far more complex than a simple crafting skill, engineering is a rare gift among the people of Rokugan, even the samurai who rule over it. It involves an understanding of how things are constructed and, as a result, how they can best be deconstructed. The siege engineers of the Kaiu family are the unquestioned masters of this, but there are others among other clans who have such gifts as well.
If artisans are tasked with producing items that are considered abstract and beautiful by the people of the Empire, then craftsmen have the duty to create things of practical value. Blacksmiths, armorsmiths, cartwrights, carpenters, and shipwrights are all craftsmen. Fishermen and farmers are as well, although they do not produce an item but rather the food that is the lifeblood of the Empire. While crafting is not an honorable and noble a profession as being an artist, it is still highly valued and looked upon without stigma.
Occupations that involve money are distasteful to the samurai caste. They are not inherently dishonorable, of course, for it is absolutely necessary for a samurai to oversee such activities to ensure that his Clan and family are adequately provided for, but it is definitely considered something of a social stigma to deal in commerce. The actual day to day trading and conducting of business is typically left to merchant vassals, but it is not unheard of for samurai to have training in such matters. These individuals are typically referred to as "merchant patrons."
Animals play a vital role in a number of samurai endeavors, including recreation, transportation, or the actual waging of war. Horses and falcons are the animals most commonly trained by samurai, but a number of others exist: the Lion Clan uses trained warcats in battle, the Unicorn use war dogs, and many families use trained pigeons to carry correspondence.
The difficulty to domesticate and train an animal for use varies widely depending upon the animal in question.