Seize the Day in Chinese / Japanese...

把握今日 is the closest and most natural way to express this proverb in Chinese.

The first two characters mean “to seize” but can also be translated as “take control of.”

The last two characters mean “today.”

現世 is a very short way to write “live in the moment” or “live in the now” in Japanese.

This short word is open to interpretation. It's used in Japanese Buddhism to mean “the current epoch” or “the current age” (the current age is but a brief moment in the greater scope of existence). In that context, this is pronounced “utsushiyo” or “ustusiyo” in Japanese. Otherwise, it's pronounced “gensei” in Japanese.

Other translation possibilities include:

Note: This is also a word in Chinese and old Korean Hanja. While the meaning is more or less the same, this is not recommended for a wall scroll if your audience is Chinese or Korean. This selection is best if your audience is Japanese.

今を生きる is a Japanese phrase that can be translated as “live for the day,” “live for the moment,” “seize the day,” or “make the most of the present.”

You can think of this as the Japanese version of “Carpe Diem.”

Note: Because this selection contains some special Japanese Hiragana characters, it should be written by a Japanese calligrapher.