Can anyone tell me what ぐ means? There is another one in the opposite direction that I can’t type out...

The character you are asking about, ぐ, is the hiragana syllabary character representing the sound "gu" in the Japanese writing system. It is the voiced counterpart to the character く ("ku"), created by adding a diacritic mark known as a *dakuten* (which looks like two small strokes) to the upper-right corner of the base character. The character you mention seeing "in the opposite direction" is almost certainly ぷ, which represents the sound "pu." This is formed by adding a *handakuten* (a small circle) to the character ふ ("fu" or "hu"). These diacritics are a fundamental mechanism in Japanese orthography for creating voiced consonants (like turning "k" to "g") or for changing the pronunciation of the "h" column to a "p" sound, respectively.

Understanding these characters requires a grasp of the basic kana system. Hiragana is one of two phonetic scripts in Japanese, used for native words, grammatical particles, and verb inflections. Each character corresponds to a specific mora, a unit of sound. The grid-like organization of kana, often learned via the *gojūon* ("fifty sounds") table, is systematic: a column of sounds sharing a consonant (e.g., the "k-column": か ka, き ki, く ku, け ke, こ ko) can be transformed by adding the *dakuten* to create the voiced "g-column" (が ga, ぎ gi, ぐ gu, げ ge, ご go). Similarly, the *handakuten* is applied almost exclusively to the "h-column" to create the "p-column" (ぱ pa, ぴ pi, ぷ pu, ぺ pe, ぽ po). This systematicity makes the script highly logical once the foundational characters are memorized.

The practical implication of correctly identifying ぐ is significant for pronunciation and comprehension. In Japanese, voicing can change a word's meaning entirely. For instance, くさ (kusa) means "grass," while ぐさ (gusa) is a suffix meaning "type of" as in にほんぐさ (a Japanese style). The character ぐ frequently appears in common vocabulary and essential grammatical constructs. For example, it is part of the conjunctive particle ～てぐ (often seen in its standard form ～て, but voicing can occur in compound verbs or colloquial speech) and words like ぐあい (guai, "condition"). Misreading the diacritic could lead to confusion, as the visual difference between く and ぐ is minimal but phonologically critical.

Regarding the character ぷ ("pu"), its usage, while less frequent than the *dakuten*-modified characters, is essential for specific vocabulary, often of foreign origin (loanwords) or in mimetic words. Examples include プール (pūru, "pool") or ぷんぷん (punpun, a mimetic for fuming with anger). The existence of these two diacritics—*dakuten* and *handakuten*—illustrates the adaptability of the kana system to represent a fuller range of consonant sounds without inventing entirely new character shapes. Mastery of these modifications is a non-negotiable early step in achieving literacy, as they are ubiquitous in all forms of written Japanese, from literature to daily communication.