XEL: Make 10 Puzzle Battle

**FLIP A NUMBER, FIND ANOTHER.**

【Game Overview】
XEL is a head-to-head numeric puzzle played on a 5×5 board, where victory is achieved by creating a total of “10.”
Place, read, strike—the outcome hinges on a single action at a time, combining logic and psychology in every move.
The rules are simple, but the decisions are deep. Matches are short, yet every game unfolds with different tactics and thrilling mind games.

【Core Rules】
■ Board & Deck
・Board: 5×5, 25 squares
・Deck: one copy each of number cards 1–9 + four SUM cards (total 13)
・Hand: always 3 cards (immediately refilled after use)

■ Turn System
・On your turn, you may place 1 card only
・Used cards are discarded and never reused
・Victory is checked at the end of every action

■ Victory Condition (SUM Card)
・When playing a SUM card, choose one of the 8 directions (orthogonal or diagonal)
・If the total of all number cards along that line equals exactly 10, you win instantly
・The SUM card itself does not count / empty squares count as 0
・If both players achieve victory simultaneously, the active player wins

■ Perspective Rule (numbers change depending on orientation)
・1, 2, 5, 8 … same for both players
・6 ↔ 9 … reversed
・3, 4, 7 … appear as “0” from the opponent’s view
→ A situation may arise where “10 for me” is not “10 for them,” forming the heart of the mind game

【Game Tempo】
■ One Move, One Decision
・With only “place or not” to choose, every single move carries weight
■ Quick Matches
・Each game lasts a few minutes—perfect for spare time yet dense in strategy

【Strategic Highlights】
■ Card Scarcity
・Each number card (1–9) exists only once—misuse and the opponent will punish you
■ Using Perspective Differences
・Combine 3/4/7 as “0” from the opponent’s view, or flip 6/9 to shift line values
■ Line Planning & Bluffing
・SUM direction can be offensive or deceptive. Even pointing outside the board can disrupt the opponent’s math
■ Value of Turn Order
・Simultaneous victories favor the active player—controlling turn timing is critical

【Accessibility】
■ Simple Yet Deep
・Minimal memorization. The universal rule of “make 10” is instantly understood
■ Mental Training
・Sharpen intuition, arithmetic, spatial reasoning, and opponent simulation naturally
■ Fairness Across Ages
・No fast reflexes needed. Pure thinking equals pure strength

【Mode Policy】
・Current version focuses on the “core rule experience” (no skills, pure SUM battles)
・Built for short, repeatable sessions (analyze → rematch → improve loop)

【Monetization & Stamina】
■ Free-to-Play with stamina system
・Daily play available for everyone
■ Options (initial lineup)
・Remove Ads ($5 one-time): disables banner & interstitial ads
・Full Stamina Restore ($2): instantly recover when you run out
・1-Hour Unlimited ($3): play without stamina for 1 hour (ads remain)
■ Fairness
・Purchases never affect player strength. Monetization is limited to comfort and play volume

【Design Philosophy】
■ Strict Rules, Intuitive Play
・Clear enough to explain on one page, yet deep enough for serious thought
■ Sustainable Solo Development
・Replay value comes from the elegance of the rules, not sheer content volume
■ Visible “Reading”
・Perspective, line sums, and turn order create a sense of progress—the more you understand, the stronger you get

【Future Plans (Concept Stage)】
・Planned skill expansions: ROTATE / MOVE / WARP / LOCK / SWAP / DELETE
・Current release is pure SUM rules only—first enjoy the unadorned beauty of the system
※ Names and details may change during development

【Recommended For】
■ Fans of Sudoku, Othello, or Chess who enjoy logical battles
■ Players who want a simple rule with deep outcomes
■ Those who enjoy short, intense matches on repeat
■ Thinkers who want to balance intuition and logic
■ Anyone looking for a fresh type of numeric puzzle