By successfully sequencing the entire genome of common wheat (Triticum aestivum L.) in 2018, the International Wheat Genome Sequencing Consortium (IWGSC) achieved its goal of publishing the first reference genome sequence of this important crop. During this period, various technological innovations have dramatically evolved genome sequencing technology; these advances have made it possible to rapidly decode large and complex genomes, including that of polyploid wheat. IWGSC completed reference genome sequence by exploiting these latest technologies via two primary approaches, “whole-genome sequencing” and “sequencing by chromosome.” As collaborators in the IWGSC project, a Japanese research team led by the National Agriculture and Food Research Organization was responsible for sequencing chromosome 6B, one of the 21 wheat chromosomes, and contributed to constructing the reference genome sequence. This article presents an outline of reference genome sequence construction and provides an overview of the common wheat genome information obtained. Moreover, it describes the methods used to sequence chromosome 6B, together with the associated analytical data and novel knowledge, including the structural analyses of Nor-B2 and Gli-B2 obtained during this work. Furthermore, it describes the recently undertaken sequencing of the genomes of diploid and tetraploid wheat and reviews the overall development of wheat genomic resources.