Korean immigrants
During the 660s, large numbers of Korean immigrants entered Japan following the Tang invasions of Korea … we know this both from Nihon shoki references as well as from the Korean styles and methods indicated in architecture, art and artefacts of the time. The immigrants came in two waves, one in 663 from Paekche and another in 668 from Koguryo.
From the Nihon shoki report, in the 663 migration wave, four hundred Paekche commoners were settled in the province of Omi, probably where new land was opened up for cultivating rice. According to the same report, one high-ranking Paekche refugee was granted court rank in Japan. Shortly after, two former Paekche ministers of state arrived in Japan with more than seven hundred Paekche men and women who were subsequently settled in the Kamo District of Omi Province.
In the second wave of migration, 56 persons from Koguryo were settled in the province of Hitachi and 1,799 more Koguryo migrants were placed in Suruga as well as elsewhere in the east.
Many of the immigrants were members of the elite, and among the Korean migrants flooding Japan were artisans, builders, administrators and various specialists whose special knowledge and services were used to strengthen the state, increase revenues and implement controls. In the year 671 as many as seventy Paekche officials were awarded Japanese court rank.
The various fields in which these immigrants specialized e.g., military science, medicine, yin-yang philosophy, Confucian classics and the high ranks conferred upon them showed the Japanese court intended to make extensive use of Korean experts in what was probably an accelerated program of modernization of the country.
Out of Paekche to Japan also came calendar makers, priests and diviners, temple builders, bronze casters and roof tile makers, specialists on continental music and dance and Chinese court ceremonies.
Contact with China
Until the year 600, Chinese ideas, technology and influences came via Korea (particularly Paekche). The year 600 was the year when Empress Suiko despatched an official mission to China’s Sui court. Thereafter in the 7th century there was a huge increase in flow of methods and ideas directly from China.
China in the 6th century had become unified under General Yang Chien and following the new Sui dynasty, visitors to China including the Japanese, were dazzled by China’s walled palace-city, empire-wide canal system and other building projects; they were impressed by the complex bureaucracy that effected efficient control, by the detailed codifications of the law and the Confucian ideology in which emperors were honored as Sons of Heaven, and who commanded obedience; the Taoist teachings that legitimized imperial control.
Through establishing its contacts with the continent, Japan then sought after the following:
1) the use of administrative techniques for increasing state power and for building of a powerful Chinese-style state
2) various forms of Chinese learning.
3) the techniques of Chinese art(s)
4) the adoption of Chinese-style codes or codifications.
Heritage of Japan 
Do you know the year of the first wave of immigrants entered Japan ?
As mentioned in the article, the official date of the first wave of immigrants during the Asuka period by Nihon shoki was 663.
However, there were many waves of immigrants throughout prehistoric times continuing through to this date. It is doubtful that this official date represents the only immigration wave. There would have been immigrants trickling into the archipelago given the many landing points all over the country. Academics have also mentioned that the “first” Buddha introduced at court that was recorded in the texts was probably not the first one to arrive in Japan either, that smaller Buddhas were installed in homes of Korean immigrants in the provinces in Japan elsewhere.