How are the essential graphical identities of kanji defined? The length of the first stroke in 土, for example, is essential, because if it's longer than the third stroke, you have 士 instead. If you get that wrong, you get the kanji wrong. But the angle of the first dot stroke in 火, for example, is not essential. The KanjiVG diagram for it shows it descending to the right, but in the font that displays for me on this page, it descends to the left. Similarly, the first stroke of 言 can apparently be either a dot or a horizontal. None of the resources I've looked at have explained either of these things or explained what they mean for me if I want to write Japanese by hand. (UPDATE: answers linked in the comments relating to 教科書体 have explained the variations in the appearances of forms of 言 and 火. Thank you!)
This is a really weird and obscure analogy, but it's the best one I can come up with:
In traditional European heraldry, each coat of arms granted by the state must be given a description in a formal language called blazon that fully defines the design. An illustrator who understand this language can read the definition and translate it into an image that legally counts as that coat of arms. Paraphrased into modern vernacular, the Royal Arms of England are defined as a red field with three gold lions walking [to the left] and looking aside, vertically arranged, with blue tongues and claws.
Heraldic tradition predates the geometrically based art techniques of the Renaissance, so exact proportions don't matter. As long as your picture fits the description above, it is the Royal Arms of England. Art style and even art quality are irrelevant. Codified in the grammar and semantics of blazon is an abstract set of rules that establish how all the design elements fit together to define the unique identity of a person's coat of arms, so that different designs can be identified even when haphazardly scrawled by the errant hands of the sloppiest Medieval artists.
Do the Ministry of Education's canonical lists of kanji have similarly essentialized definitions of character forms? Are there other resources where I can find similar information? I want to improve my penmanship, but I'm not entirely clear on what constitutes good penmanship. RTK has been helpful in learning the basic components that make up a kanji and their approximate relative positions, but it tends to leave the deeper questions of "What makes this kanji this kanji as opposed to that kanji?" and "Where is this stroke supposed to go, how long is it supposed to be, and how strict are those specifications?" unanswered. Stroke diagrams alone don't give you this information because they just show one example of how a kanji can look. Where I can read explanations of what kanji are supposed to look like?
Some examples of the general sort of thing I have in mind:
- 一 is a ㇐.
- 二 is a ㇐ over another, longer ㇐.
- 三 is 二 with a shorter ㇐ interjected.
- 十 is a ㇐ bisected by a longer ㇑ intersecting above the midpoint of the second.
- 土 is 十 with a wider ㇐ appended.
- 士 is 十 with a narrower ㇐ appended.
- 口 is a ㇑ cooriginating with a ㇕ descending as far as the previous, followed by a ㇐ between the endpoints of the first and the second.
- 言 (in its regular script form) is, from top to bottom, a ㇔, a ㇐, two shorter ㇐'s, and a 口 as wide as the previous.
- 五 is a ㇐, a ㇑ descending leftward from left of the midpoint of the first; a ㇕ bisecting the second with its horizontal part, narrower than the first and descending to the end of the second; and a ㇐ longer than the first running over the endpoints of the two previous.
- 吾 is 五 over a 口 as wide as the third stroke of the previous.
- 語 is 言 beside 吾.
- 日 is a narrow 口 with an interjected ㇐ between the midpoints of its first and second strokes.
- 曰 is a 口 with an interjected ㇐ from the midpoint of its first stroke nearly to that of its second.
- 白 is a 日 with a leftward 丶 prepended.
- 百 is a 白 with a wider ㇐ prepended.
- 昌 is 日 over another, wider 日.
- 唱 is an elevated 口 beside 昌.
- 寸 is a ㇐ intersecting a ㇚ on the upper right, with a ㇔ between the two on the lower left.
- 専 is a wider ㇐ over 日 all bisected by a ㇑ from above the first to the midpoint of the last stroke of the second, with a 寸 appended.
- 博 is a 十 with an elevated second stroke beside a 専 with a 丶 interjected up and to the right of the first stroke of the second.
The formal conventions of and some of the terminology in the above examples are invented for the nonce, and of course, it's all in English. Any similar natural-language definitions in Japanese would be very different. I also don't imagine that any existing document would be precisely as specific as I have been in these examples; they could be more ambiguous or they could be even more precise.
The Ministry of Education has lists of kanji for general use, for use in names, etc. Do any of these lists or the documents associated with them contain such formalized natural-language definitions of the kanji those lists are supposed to standardize, or are they all just picture of kanji, picture of kanji, picture of kanji?