In Japan, it is customary to bow when greeting someone, especially in a business setting. It is also important to remove your shoes when entering a home or certain establishments, such as traditional tea houses. Respect for authority and hierarchy is also highly valued in Japanese culture. As for taboos, it is considered rude to be loud or express strong emotions in public, and it is important to handle business matters delicately and with proper decorum.
In South Korea, it is customary to greet someone with a small bow and a handshake. Respect for elders and those in authority is also highly valued, and it is common to address them with formal titles. Gift-giving is also an important part of Korean culture, although it is important to be aware of what is appropriate to give in different situations. As for taboos, it is important to avoid showing the soles of your feet and to always use both hands when passing an object to someone else.
When dealing with clients from Japan or South Korea, it is important to be aware of and respectful of their customs and taboos. Dressing professionally and conservatively is important in both cultures. It is also important to be punctual and to address clients with proper titles and honorifics. Gifts may also be appropriate in some situations, but be sure to research what is appropriate beforehand. Additionally, it is important to avoid confrontations and to handle business matters with discretion and politeness.