Ngo in Chinese / Japanese...

ンゴ is the name Ngo in Japanese Katakana.

Note: Because this title is entirely Japanese Katakana, it should be written by a Japanese calligrapher.

This is the surname Ng in Chinese.

吳 is sometimes romanized as Ang, Eng, Ing and Ong in the United States and Ung in Australia. In Mandarin, 吳 is usually romanized as Wu, but sometimes Woo. In Vietnamese, 吳 can be the Ngô surname.

Be careful, as 黃/黄 is another surname character that also romanizes as Ng and other variants noted above.

剛柔 is a term that means hardness and softness or hard and soft.

剛柔 is also the Chinese character origin of the martial arts style known as Cương Nhu.

Cương Nhu or Cuong Nhu was founded by Grandmaster Ngo Dong in 1965 in Hue, Vietnam, and brought to the U.S. in 1971.

剛 means hard, firm, strong, and just.
柔 means soft, flexible, supple, yielding, softness, and/or gentleness.

Until it was romanized in the mid-17th century by Portuguese missionaries with later influence by French missionaries, Vietnamese was exclusively written in Chinese characters. With some research, you can still figure out the original way to write most Vietnamese words and titles in Chinese characters. That is what I did here to figure out that Cuong Nhu would have been 剛柔 if established in ancient Vietnam.

Same characters are used in Japanese for various Goju schools of Okinawan martial arts, though not the same lineage as the Vietnamese style described above.