Poetic fragmental sentences such as Haiku are often free from grammatical constraint while maintaining full message transmitting power. The author takes Haiku, a classical Japanese concise poetic sentence, as an elegant and efficient communication language for a digital signal system. By using the functional grammar and season-word ontology, the author will throw light on the secret of efficiency in Haiku-like sentences. It is often said that this efficiency comes from artistic mutism—ellipsis or abbreviation. Various events and situations are narrated in a very short and simple sentence, which is composed of a 5-7-5 pattern of letters, words, or phrases. Haiku-like sentences can be composed in non-Japanese, such as English, French, Chinese, etc. The most important Haiku philosophy is “the universality” (Fueki-Ryukou), which was first told by the great poet Basho in 1689. The benefit of universality is even ranging over the digital communication system. That is, the Haiku-like sentence enables highly efficient and concise communication. You can so much as write a cipher by Haiku.