"What?? You never told me that! How was I supposed to know??"
Too often communication between Japanese and people from Western societies goes astray in this way. Japanese communication style is considered to be an implicit one, epitomized in their proverb, "Hear one, understand ten." In other words, for each point expressed, the listener is expected to understand at least nine others by implication. Since the most important part of the conversation is often left unspoken, it becomes the responsibility of the listener to pick up on what has been implied, or otherwise indicated in a nonverbal way, and "read" the contextual clues, such as who said what, when, where, how and in whose presence.
Japanese are trained from a young age to read or detect others' unspoken thoughts and intentions through guess or conjecture of what they are thinking. Those who are not able to do this well are thought to be "clueless" or mentally slow, and are considered ineffectual in the workplace. As one Japanese said to me, "We aspire to have relationships where no words are necessary." Consequently, much of what happens in the work place literally "goes without saying."
Japanese will even intentionally avoid being too explicit because it could be seen as an insult, implying that the other person was unknowledgeable. It's thought you would only need to say everything to idiots - others would understand by implication, or by reading the atmosphere and getting the "vibes." And these people who are more dense are popularly referred to as K.Y. standing for kuuki ga yomenai, literally unable to "read the air."
This implicit style works best when the listener has plenty of background information. Therefore, when a relationship is just beginning or a new project is embarked upon, Japanese will want to gather as much contextual information as possible. And at this beginning stage it's not uncommon for them to unleash a whole host of direct questions in order to construct that contextual framework. Data and information of all kinds are needed to create a deep, shared understanding where telepathic messages are then easily understood.
So if you are working with Japanese as an employee, a supplier, a joint venture partner, or in any other type of relationship, it behooves you to gather as much information as you can as well. This may mean asking more questions back, tapping various colleagues for additional information, or doing research online. It is also in your interest to start paying attention to subtle indicators of a telegraphic message. Relatively small clues may suggest that something is more important than you would expect or that the subject under discussion is going sour.
You"ll need to get good at reading between the lines by paying attention to more than just what's communicated explicitly.
Otherwise, you are likely to hear one and understand none.