In 871 BC, the closest thing to a modern shirt was the tunic or כֻּתֹּנֶת keh-TOH-net. Most hung from neck to ankles and tied at the throat.
These drawings below from an Egyptian tomb show people from the East — perhaps the Middle East — entering Egypt about 1900 BC.
Notice how the outer garment serves as a wrap that leaves one shoulder and both arms free. The nearest Biblical contemporaries of these people were the early Hebrews, such as Abraham.
This next photo, from the Black Obelisk, shows a rare depiction of Hebrew clothing. King Jehu, the one who drove furiously, or possibly his ambassador, kneels at the feet of Shalmaneser III.
I use these photos by permission from NebMaatRa.