One purpose of this article is to master correct1y present situation of examination for inventive step in Japanese courts. One reason why inventive step is considered as a difficult research topic is that in Japan there appears near1y 300 judgments re1ated to inventive step each year. However, acadernia in Japan just introduces on1y a small few of these cases whereas a 1ot of papers are published to discuss these small few ones. For this reason, considering the 300 judgments made every year, this kind ofthe present methodo1ogy mentioned above fai1s to get a who1e picture on examination of inventive step. For the first time in Japan, the article here studies by using a statistical approach on approximately 700 judicatory cases which are between 2009 to 2012, in order to disclose present situation of examination for inventive step. The summary is as follows: After analyzing judicatory cases in Japan re1ated to inventive step, it is found that these cases cou1d be divided as conventiona1 type and 1ogica1 type. The conventiona1 type means that: a) identify a document as primary prior art; b) then without assessment of thought process of a person skilled in the art starting from the primary prior art, as long as a claimed invention is considered as be1onging to prior arts, a conclusion of 'it is easi1y able to arrive at the invention' wi11 be made. While the logical type means that: a) identify a document as primary prior art; b) then identify a document as secondary prior art etc. and apply them to primary prior art to try forming the claimed invention; c) based on the conventional type approach, an additional step is included here paying attention to determine whether it is possible to reason that there is motivation in a thought process starting from the primary prior art to arrive at the claimed invention after a filing or priority date. According to the USA TSM test, as long as there is no 'teachings, suggestion, or motivation' (limited enumeration) appearing in prior arts, it is not able to make a patent invalid. Therefore, when the TSM test is used, a patent become most difficult to be made invalid. If the TSM test is considered as a closed/rigid approach, the logical type mentioned above, different from the TSM test, is an open approach because it is not necessarily limited to 'teach, suggestion and motivation'. Two conclusions in the present article are obtained as fol1ows. First1y, the present situation of examination for inventive step in Japan is that both of the conventional type and logical type exist and using conventional type is sti11 deep-rooted. Indeed, compared with the conventional type by use of which a patent is most easily to be made invalid, the logical type is a majority in Japan. On the contrary, in the USA, due to judgment of KSR, a strict use of the TSM test leading a patent most difficult to be made invalid has turned to use TSM test in a f1exible manner. Therefore, there is a trend that Japan and the USA is approaching to each other due to an existence of a middle zone between the conventional type and the rigid use of TSM test. However, there are sti11 a considerable number of cases using the approach of conventional type in Japan. Secondly, as mentioned above, if approaches for examination of inventive step are recognized as three ones in the order of conventional type, logical type and TSM test, accordingly, the invalid rate of a patent becomes theoretically lower and lower. For this reason, it becomes clear that a country selectively using one of the three approaches for examination of inventive step could transfer subtly corresponding state policy to its patent system.