Guides
Deep dives by topic: formulas, assumptions, common mistakes and worked examples.
Hiragana vs Katakana
Usage, shapes and learning order.
指南 · GuideSpaced Repetition and the Forgetting Curve
1/3/7/14/30/60/120-day intervals and daily planning.
指南 · GuideOn Readings vs Kun Readings
Where the two reading systems come from and when they appear.
指南 · GuideAn N5 Kanji Study Order
From numbers and nature to people, school and transport.
指南 · GuideHow to Study N4 Kanji
By theme, with vocabulary, and by distinguishing similar characters.
指南 · GuideFrom N5 to N4
Kana, N5 kanji, N4 kanji, vocabulary and grammar.
指南 · GuideA Plan for N4 Vocabulary
Themes, collocations, examples and output.
指南 · GuideThe Full N4 Path
Kana, N5, N4 kanji, N4 vocabulary, grammar and reading.
指南 · GuideHow to Study N4 Grammar
Connections, examples, contrasts and output.
指南 · GuideWhere N4 Grammar Fits
The order of kana, kanji, vocabulary, grammar and reading.
指南 · GuideAn IELTS Vocabulary Plan That Sticks
High-frequency words, examples, spaced review and output practice.
指南 · GuideUsing Academic Words in Writing
Collocations, word forms, examples and avoiding word salad.
指南 · GuideSpanish Pronunciation Basics
Five vowels, stress, ñ and common consonants.
指南 · GuideA 60-Word Spanish Plan
Ten words a day, examples, review and output.
指南 · GuideWhat to Learn First in Python
Variables, containers, control flow, functions and modules in order.
指南 · GuideCommon Python Traps
Mutable defaults, shallow copies, integer division, is vs ==.
指南 · GuideDaily Git Workflow
The status, diff, add, commit, pull and push loop.
指南 · GuideUndo and Recover in Git
Choosing between restore, reset, revert and reflog.
指南 · GuideExcel Formula Basics
References, absolute/relative, errors and IF.
指南 · GuideVLOOKUP, XLOOKUP and INDEX+MATCH
When to use each lookup and common errors.
指南 · GuideThe Word/PPT Shortcuts Worth Learning
Save, undo, formatting, slideshow and alignment.
指南 · GuideA Keyboard-First Presentation Workflow
From new file and layout to slideshow, using keys.
指南 · GuideMental Math Strategies
Rounding, splitting, times tables and exact division shortcuts.
指南 · GuideTimes Tables That Stick
From 2/5/10 to 7/8/9, practiced on a forgetting curve.
指南 · GuideSQL SELECT Basics: WHERE, ORDER, LIMIT
The minimal query structure for filtering, sorting and limiting rows.
指南 · GuideSQL JOIN and GROUP BY
Joining two tables, aggregate groups and HAVING.
指南 · GuideHow to Read Python Output
Expressions, repr, operator precedence and common traps.
指南 · GuideList and Dict Output: Slices, Comprehensions, get
Slice bounds, list comprehensions, dict keys and get defaults.
指南 · GuideHow to Read JavaScript Output
Operators, coercion, truthiness and JSON formatting.
指南 · GuideReading map, filter and reduce
What array methods return, callback arguments and chaining.
指南 · GuideRegex Basics: Classes, Quantifiers, Anchors
\d, \w, +, *, ?, ^, $ and escaping.
指南 · GuideGroups, Greediness and Lookaround
(), (?:), greedy/non-greedy and (?=)/(?<=).
指南 · GuideTenses and Subject-Verb Agreement
Present/past, perfect tenses and third-person singular.
指南 · GuideArticles, Prepositions and Passive Voice
a/an/the, collocations and was/were + past participle.
指南 · GuideLearning English, French and Spanish Together
Main language, maintenance language and cognate strategy.
指南 · GuideCognates and False Friends
Similar-looking words in English, French and Spanish: when to guess and when not to.
指南 · GuideHow to Read the Periodic Table
Periods, groups, atomic number and atomic mass.
指南 · GuideIons and Isotopes
Charges, electron gain/loss and neutron counting.
指南 · GuideRemembering Countries and Capitals
Group by region, locate on a map and learn English names.
指南 · GuideRegions, Currencies and ISO Codes
Regions, three-letter currency codes and two-letter country codes.
指南 · GuidePhysics Formulas and Units
Formulas and units for speed, density, force, work, power and pressure.
指南 · GuideOhm's Law and Electric Power
U=IR, P=UI, series/parallel and units.
指南 · GuideArea and Perimeter Formulas
Rectangles, squares, triangles, circles and trapezoids.
指南 · GuideVolume and Surface Area Formulas
Cuboids, cylinders, spheres and cones.
指南 · GuideSpanish Regular Verb Endings
-ar/-er/-ir endings across five tenses.
指南 · GuideUsing Five Spanish Tenses
When to use present, preterite, imperfect, future and conditional.
指南 · GuideFrench Regular Verb Endings
-er/-ir/-re endings in present, imperfect, future and conditional.
指南 · GuideUsing Five French Tenses
Present, imperfect, future, conditional and passé composé.
指南 · Guide