The zero was probably introduced to the Chinese in the Tang dynasty (618–907) when travel in the Indian Ocean and the Middle East would have provided direct contact with India, allowing them to acquire the concept of zero and the decimal point from Indian merchants and mathematicians.
ðə zˈiəɹoʊ wʌz pɹˈɑːbəbli ˌɪntɹədˈuːst tə ðə tʃaɪnˈiːz ɪnðə tˈæŋ dˈaɪnɐsti sˈɪkshˈʌndɹɪd ˈeɪtiːn nˈaɪnhˈʌndɹɪd sˈɛvən wɛn tɹˈævəl ɪnðɪ ˈɪndiən ˈoʊʃən ænd ðə mˈɪdəl ˈiːst wʊdhɐv pɹəvˈaɪdᵻd dᵻɹˈɛkt kˈɑːntækt wɪð ˈɪndiə, ɐlˈaʊɪŋ ðˌɛm tʊ ɐkwˈaɪɚ ðə kˈɑːnsɛpt ʌv zˈiəɹoʊ ænd ðə dˈɛsɪməl pˈɔɪnt fɹʌm ˈɪndiən mˈɜːtʃənts ænd mˌæθɪmɐtˈɪʃənz.