Recently, I have been focusing intensively on preparing the detailed schedule for the research journey that will begin in September, as well as on matters that should be investigated in advance. Among these, the question I have pursued most over the past seven years is how the movements of the Jomon people within the Japanese archipelago laid the foundation for a multi-sourced cultural environment that ultimately led to the modern Japanese people. To clarify this, as has long been suggested, it is necessary to examine the processes by which the ancestral groups who would later be called the Jomon entered the ancient Japanese archipelago via both northern and southern routes from the continent.
However, although research based on this assumption has been carried out for decades in various fields, it remains a major mystery with no clear conclusion. In essence, while it is generally accepted that people began settling in the Japanese archipelago through these two main routes, how this migration actually occurred is still unknown. Based on the topography of the time and lowered sea levels, it seems plausible that the northern route allowed direct access from Sakhalin to the Wakkanai area at the northern tip of Hokkaido, or that the journey could have been completed with only a short voyage. Even so, if that were the case, there should be cultural connections between the Sakhalin area and northern Hokkaido. Yet, traces of such connections are almost entirely absent.
The Jomon period has long been defined by archaeological artifacts such as pottery styles, yet from this perspective, Sakhalin and northern Hokkaido differ greatly in character, making it difficult to identify any continuous Jomon cultural linkage. Another possibility that has drawn attention is the island-hopping route via the Kuril Islands. This route involved traveling by boat from Siberia, hopping across multiple islands, and eventually reaching the Shiretoko or Nemuro regions of Hokkaido. Interestingly, cultural similarities to the Jomon have long been noted on this side.
However, since World War II, this region has been overshadowed by the Northern Territories dispute between Japan and Russia, with each side conducting its own surveys at different times. Due to diplomatic constraints, consistent, unified research has been impossible, and the mystery remains unresolved. It is therefore expected that it will take considerable time before the full picture of this route emerges, making the normalization of relations between the two countries an urgent task.