For nouns, which are formed by compounding two different nouns, the accent patterns are different from the original words when pronounced separately. Even if there is an accent nucleus when pronouncing each word separately, the accent pattern will change when compounding the words into one. The reason is that there can only be one accent nucleus in a word. For example, when the first component haru ( はる（春） spring)compounds with the second component yasumu yasumi (やすみ （休み）holidays) to form haruyasumi (spring holidays), the accent is not ha ruyasumi, but haruyasumi (はるやすみ).
To some extent, there are rules regarding accent patterns of compound nouns. If you remember these rules and memorize those exceptions which do not conform to these rules, it will be easier to acquire the accent patterns of compound nouns. The following table summarizes the rules of the accent patterns of compound nouns.