How can I find the patent of my competitor?
There are many free online search tools available from the patent offices. One of the most reliable and powerful is from the EPO (http://www.epo.org/searching-for-patents/). In order to find the patent of your competitor you must first identify the correct business name.
E.g.: search for BMW does not lead to all the patents, but. "Bayerische Motoren Werke" is the correct name of the entity. Secondly, you must be sure of all relevant subsidiaries of your competitor.
In performing the patent search you type in the name of your competitor and set wildcards, example: "Bayer * Motor * Werk *", because sometime there are typing mistakes in the datasets.
Last but not least; search becomes complex if you want to identify a patent in a country without digitalized patent information, like Vietnam. Here you will need local assistance from e.g. a patent attorney.
If your competitor has too many patents, than you have to make combinations in search; for example words in title or in the abstract.