－Kobo-Daishi "Twice to China Theory"－ ■　Why did the Blank Decade Occur?　■  Many things remain unknown about the traces of Kobo Daishi during a period of about ten years before his visit to Tang in a Kentoshi ship (from his writing of "Sango Shiiki" until entry into Tang). 　All of the explanations about this period given in the biographies of Kobo-Daishi, published during the pre-war and post-war periods and since to date, remain a matter of speculation. One of the representative biographical books on Kobo-Daishi is the Reverend Kakusho Takagami's. In this book, he wrote: "There are no materials worth noting regarding the life of Kukai during this ten year period, but it may probably be said that this period was devoted to preparations for traveling to Tang." In another representative book by the two reverends, Shoko Watanabe and Yusho Miyasaka (1967 edition), reads: "Clues to Kukai's whereabouts suddenly disappeared. …. No literatures or records are left at all." 　In his well known novel "Kukai-no-Fukei" (Kukai the Universal), Ryotaro Shiba also mentioned that "there are many years of blankness" and explained this blank period as the years of ascetic practice at various locations in Japan. In short, nothing is known about this period. Recently, I had a very strange experience in relation to this "blank decade" of Kobo-Daishi. 　One night, in an inspired dream in which Kobo-Daishi, or Kukai, appeared, I was able to have an opportunity to friendly ask him about his traces during the blank period. What I describe below is a story based on the words spoken by Odaishisama, organized to facilitate understanding by general readers. 　In the Western world, there is a parable called the "Egg of Columbus." It is used to demonstrate that something that appears difficult is very simple once the trick is revealed. Analogously, the explanation given by Kobo-Daishi about the blank decade was as simple as that he was not in Japan but was staying in China. The reason for the lack of any records or documents about his traces was his absent from Japan. 　The lack of documents explaining about ten years before traveling to Tang made these years a mystery within the history of Kobo-Daishi, but a question still remains: Why did Kobo-Daishi keep silent about the decade? The primary reason for this decade being a mystery is attributable to nothing but to the absence of any explanations by Kobo-Daishi himself. 　To lay a foundation for understanding this issue, let us first identify several questions. 　The first question is: Is not it more important to seek to clarify why the blank decade occurred, than attempting reasoning over how Kobo-Daishi utilized the years? This question has hardly been addressed by the biographical books on Kobo-Daishi published so far. 　One argument for the occurrence of such a period that somehow appears to be reasonable is that Kobo-Daishi lived so long ago that no records have managed to survive. However, when it comes to Kobo-Daishi, the argument that blames a lapse of over a thousand years for the occurrence of the blank decade does not seem to be viable. Kobo-Daishi, in fact, was a prolific note taker. Looking at the documents and records that were compiled into Shoryoshu (a garland) or other works, one would agree that Kobo-Daishi presumably always carried a carefully prepared filing case with him. Otherwise, it would have been impossible for him to leave life-time written records for posterity one millennia ago. Anyone who is engaged in literary work in one way or another would know through his/her own experience that, even in the modern times, when copy machines are readily at hand, how difficult it is to maintain a life-time personal record. Therefore, scattering and loss of documents over time is not a probable reason in the case of Kobo-Daishi. Rather, it would be more justifiable to consider that this "blank decade" was created intentionally by Kobo-Daishi himself.