diff --git a/Data/Kanji.hs b/Data/Kanji.hs
--- a/Data/Kanji.hs
+++ b/Data/Kanji.hs
@@ -16,34 +16,27 @@
        , allKanji
        , isKanji
        , hasLevel
-       , kanjiDensity
-       , elementaryKanjiDensity
-       , percentSpread
          -- * Levels
        , Level(..)
        , Rank(..)
        , level
        , levels
        , isKanjiInLevel
-       , levelDist
        , levelFromRank
+         -- * Analysis
+       , kanjiDensity
+       , elementaryKanjiDensity
+       , percentSpread
+       , levelDist
        , averageLevel
        ) where
 
+import           Data.Bool (bool)
 import           Data.List (sort, group)
 import qualified Data.Set as S
 import           Lens.Micro
 
-import           Data.Kanji.Level.EighthQ
-import           Data.Kanji.Level.FifthQ
-import           Data.Kanji.Level.FourthQ
-import           Data.Kanji.Level.NinthQ
-import           Data.Kanji.Level.PreSecondQ
-import           Data.Kanji.Level.SecondQ
-import           Data.Kanji.Level.SeventhQ
-import           Data.Kanji.Level.SixthQ
-import           Data.Kanji.Level.TenthQ
-import           Data.Kanji.Level.ThirdQ
+import           Data.Kanji.Levels
 import           Data.Kanji.Types
 
 ---
@@ -51,10 +44,11 @@
 -- | All Kanji, grouped by their Level (級) in ascending order.
 -- Here, ascending order means from the lowest to the highest level,
 -- meaning from 10 to 1.
-allKanji :: [[Kanji]]
-allKanji =  map asKanji ks
-  where ks = [tenthQ, ninthQ, eighthQ, seventhQ, sixthQ,
-              fifthQ, fourthQ, thirdQ, preSecondQ, secondQ]
+allKanji :: [S.Set Kanji]
+allKanji =  map f ks
+  where f = foldr (\k s -> bool s (S.insert (Kanji k) s) $ isKanji k) mempty
+        ks = [tenth, ninth, eighth, seventh, sixth,
+              fifth, fourth, third, preSecond, second]
 
 -- | Is the `Level` of a given `Kanji` known?
 hasLevel :: Kanji -> Bool
@@ -62,8 +56,8 @@
 
 -- | What is the density @d@ of Kanji characters in a given String-like
 -- type, where @0 <= d <= 1@?
-kanjiDensity :: AsKanji a => a -> [Kanji] -> Float
-kanjiDensity orig ks = fromIntegral (length ks) / len orig
+kanjiDensity :: Int -> [Kanji] -> Float
+kanjiDensity len ks = fromIntegral (length ks) / fromIntegral len
 
 -- | As above, but only Kanji of the first 1006 are counted (those learned
 -- in elementary school in Japan).
@@ -72,13 +66,9 @@
   where elementaryQs  = filter (\(qn,_) -> qn `elem` [Five, Six ..]) dists
         dists = levelDist ks
 
-makeLevel :: [Kanji] -> Rank -> Level
-makeLevel ks n = Level (S.fromDistinctAscList ks) n
-
 -- | All `Level`s, with all their `Kanji`, ordered from Level-10 to Level-2.
 levels :: [Level]
-levels = map f $ zip allKanji [Ten ..]
-  where f (ks,n) = makeLevel ks n
+levels = map (uncurry Level) $ zip allKanji [Ten ..]
 
 -- | What `Level` does a Kanji belong to?
 level :: Kanji -> Maybe Level
diff --git a/Data/Kanji/Level/EighthQ.hs b/Data/Kanji/Level/EighthQ.hs
deleted file mode 100644
--- a/Data/Kanji/Level/EighthQ.hs
+++ /dev/null
@@ -1,15 +0,0 @@
-module Data.Kanji.Level.EighthQ where 
-
--- | The Kanji unique to Level-8, studied by the end of 3rd grade in
--- Japanese elementary schools.
-eighthQ :: [Char]
-eighthQ = "丁世両主乗予事仕他代住使係倍全具写列助勉" ++
-          "動勝化区医去反取受号向君味命和品員商問坂" ++
-          "央始委守安定実客宮宿寒対局屋岸島州帳平幸" ++
-          "度庫庭式役待急息悪悲想意感所打投拾持指放" ++
-          "整旅族昔昭暑暗曲有服期板柱根植業様横橋次" ++
-          "歯死氷決油波注泳洋流消深温港湖湯漢炭物球" ++
-          "由申界畑病発登皮皿相県真着短研礼神祭福秒" ++
-          "究章童笛第筆等箱級終緑練羊美習者育苦荷落" ++
-          "葉薬血表詩調談豆負起路身転軽農返追送速進" ++
-          "遊運部都配酒重鉄銀開院陽階集面題飲館駅鼻"
diff --git a/Data/Kanji/Level/FifthQ.hs b/Data/Kanji/Level/FifthQ.hs
deleted file mode 100644
--- a/Data/Kanji/Level/FifthQ.hs
+++ /dev/null
@@ -1,15 +0,0 @@
-module Data.Kanji.Level.FifthQ where 
-
--- | The Kanji unique to Level-5, studied by the end of 6th grade in
--- Japanese elementary schools.
-fifthQ :: [Char]
-fifthQ = "並乱乳亡仁供俳値傷優党冊処刻割創劇勤危卵" ++
-         "厳収后否吸呼善困垂城域奏奮姿存孝宅宇宗宙" ++
-         "宝宣密寸専射将尊就尺届展層己巻幕干幼庁座" ++
-         "延律従忘忠憲我批担拝拡捨探推揮操敬映晩暖" ++
-         "暮朗机枚染株棒模権樹欲段沿泉洗派済源潮激" ++
-         "灰熟片班異疑痛皇盛盟看砂磁私秘穀穴窓筋策" ++
-         "簡糖系紅納純絹縦縮署翌聖肺背胸脳腹臓臨至" ++
-         "若著蒸蔵蚕衆裁装裏補視覧討訪訳詞誌認誕誠" ++
-         "誤論諸警貴賃遺郵郷針鋼閉閣降陛除障難革頂" ++
-         "骨"
diff --git a/Data/Kanji/Level/FourthQ.hs b/Data/Kanji/Level/FourthQ.hs
deleted file mode 100644
--- a/Data/Kanji/Level/FourthQ.hs
+++ /dev/null
@@ -1,20 +0,0 @@
-module Data.Kanji.Level.FourthQ where 
-
--- | The Kanji unique to Level-4, studied during middle school in Japan.
-fourthQ :: [Char]
-fourthQ = "丈与丘丹乾互井介仰伺依侵俗倒偉傍傾僧儀兼" ++
-          "冒凡凶刈到刺剣剤劣勧匹占即却及叫召吐含吹" ++
-          "咲唐嘆噴圏坊執堅堤塔壁壊壱奇奥奴妙姓威娘" ++
-          "婚寂寝尋尽尾屈峠峰巡巨帽幅幾床弐弾彩影彼" ++
-          "征御微徴忙怒怖恋恐恒恥恵悩惑惨慎慢慮憶戒" ++
-          "戯扇払扱抗抜抱抵押拍拓拠振捕掘描握援搬摘" ++
-          "撃攻敏敷斜旨旬是普暇暦曇更替朱朽杯枯柄柔" ++
-          "桃欄歓歳殖殿汗汚沈沖沢沼況泊浜浮浸涙淡添" ++
-          "渡溶滴漫澄濁濃為烈煙煮燥爆狂狩狭猛獣獲玄" ++
-          "珍環甘畳疲療皆盆盗監盤盾眠瞬矛砲祈秀称稲" ++
-          "稿突端箇範粒紋紫紹絡継維網緯縁繁繰罰翼耐" ++
-          "肩肪胴脂脚脱腐腕腰膚致舗舞舟般芋芝茂荒菓" ++
-          "蓄薄薪被襲触訴詰詳誇誉謡豪販賦贈越趣距跡" ++
-          "跳踊踏躍軒較載輝輩込迎迫逃透途遅違遣避郎" ++
-          "釈鈍鉛鋭鎖鑑闘陣陰隠隣隷雄雅雌離雷需震霧" ++
-          "露響項頼飾香駆騒驚髪鬼鮮麗黙鼓齢"
diff --git a/Data/Kanji/Level/NinthQ.hs b/Data/Kanji/Level/NinthQ.hs
deleted file mode 100644
--- a/Data/Kanji/Level/NinthQ.hs
+++ /dev/null
@@ -1,13 +0,0 @@
-module Data.Kanji.Level.NinthQ where 
-
--- | The Kanji unique to Level-9, studied by the end of 2nd grade in
--- Japanese elementary schools.
-ninthQ :: [Char]
-ninthQ = "万丸交京今会体何作元兄光公内冬刀分切前北" ++
-         "午半南原友古台合同回図国園地場声売夏外多" ++
-         "夜太妹姉室家寺少岩工市帰広店弓引弟弱強当" ++
-         "形後心思戸才教数新方明星春昼時晴曜書朝来" ++
-         "東楽歌止歩母毎毛池汽活海点父牛理用画番直" ++
-         "矢知社秋科答算米紙細組絵線羽考聞肉自船色" ++
-         "茶行西親角言計記話語読谷買走近通週道遠里" ++
-         "野長門間雪雲電頭顔風食首馬高魚鳥鳴麦黄黒"
diff --git a/Data/Kanji/Level/PreSecondQ.hs b/Data/Kanji/Level/PreSecondQ.hs
deleted file mode 100644
--- a/Data/Kanji/Level/PreSecondQ.hs
+++ /dev/null
@@ -1,21 +0,0 @@
-module Data.Kanji.Level.PreSecondQ where 
-
--- | The Kanji unique to Level-Pre2, considerend "mid high school" level.
-preSecondQ :: [Char]
-preSecondQ = "且丙亜享亭仙伯但佐併侮侯俊俸倫偏偵偽傑傘" ++
-             "僕僚儒償充准凸凹刃剖剛剰劾勅勲升厄叔叙吟" ++
-             "呈呉唆唇唯喝喪嗣嚇囚坪垣培堀堕堪塀塁塑塚" ++
-             "塾壌壮奔奨妃妄妊妥姻娠媒嫌嫡宜宰宵寛寡寧" ++
-             "寮尉尚尼履屯岬崇崎帥幣庶庸廃廷弊弔弦彰循" ++
-             "徹忍恭悠患悼惰愁愉慶憤憾懇懐懲懸戻扉扶抄" ++
-             "把披抹拐拒拙括拷挑挟挿捜据搭摩撤撲擬斉斎" ++
-             "旋昆暁曹朕朴杉析枠枢柳栓核栽桟棚棟棺槽款" ++
-             "殉殻汁江沸泡泥泰洞津洪浄浦涯涼淑渇渉渋渓" ++
-             "渦溝滋漆漠漬漸潟濯煩爵猫献猶猿珠琴璽瓶甚" ++
-             "畝疎疫症痢痴癒盲眺睡督矯砕硝硫碁磨礁祥禅" ++
-             "禍租秩稼窃窮窯竜筒粛粧糾紡索累紳緒縄繊繭" ++
-             "缶罷羅翁耗肌肖肢肯臭舶艇艦茎荘菌薦薫藻虜" ++
-             "虞蚊蛇蛍融衡衷裕褐褒襟覇訟診詐詔誓諭謁謄" ++
-             "謙謹譜貞貢賄賓賜賠購践軟轄迅迭逐逓逝逸遍" ++
-             "遮遷還邸酌酢酪酬酷醜醸釣鈴鉢銃銘閑閥附陥" ++
-             "隅雰霜靴韻頑頒頻顕飢駄騰麻"
diff --git a/Data/Kanji/Level/SecondQ.hs b/Data/Kanji/Level/SecondQ.hs
deleted file mode 100644
--- a/Data/Kanji/Level/SecondQ.hs
+++ /dev/null
@@ -1,14 +0,0 @@
-module Data.Kanji.Level.SecondQ where 
-
--- | The Kanji unique to Level-2, considered "standard adult" level.
-secondQ :: [Char]
-secondQ = "串丼乞亀伎侶俺傲僅冥冶凄刹剥勃勾匂叱呂呪" ++
-          "咽哺唄唾喉喩嗅嘲埼堆塞填奈妖妬媛嫉宛尻岡" ++
-          "崖嵐巾弄弥彙怨恣惧慄憧憬戚戴拉拭拳拶挨挫" ++
-          "捉捗捻摯斑斬旦旺昧曖曽枕柵柿栃桁梗梨椅椎" ++
-          "楷毀氾汎汰沃沙淫湧溺潰煎熊爪爽牙狙玩瑠璃" ++
-          "璧瓦畏畿痕痩瘍眉睦瞭瞳稽窟箋箸籠綻緻罵羞" ++
-          "羨肘股脇脊腎腫腺膝膳臆臼舷艶芯苛茨萎葛蓋" ++
-          "蔑蔽藍藤虎虹蜂蜜袖裾訃詣詮誰諦諧謎貌貪貼" ++
-          "賂賭踪蹴辣遜遡那酎醒采釜錦錮鍋鍵鎌闇阜阪" ++
-          "隙韓頃須頓頬顎餅餌駒骸鬱鶴鹿麓麺"
diff --git a/Data/Kanji/Level/SeventhQ.hs b/Data/Kanji/Level/SeventhQ.hs
deleted file mode 100644
--- a/Data/Kanji/Level/SeventhQ.hs
+++ /dev/null
@@ -1,15 +0,0 @@
-module Data.Kanji.Level.SeventhQ where 
-
--- | The Kanji unique to Level-7, studied by the end of 4th grade in
--- Japanese elementary schools.
-seventhQ :: [Char]
-seventhQ = "不争付令以仲伝位低例便信倉候借停健側働億" ++
-           "兆児共兵典冷初別利刷副功加努労勇包卒協単" ++
-           "博印参史司各告周唱喜器囲固型堂塩士変夫失" ++
-           "好季孫完官害察巣差希席帯底府康建径徒得必" ++
-           "念愛成戦折挙改救敗散料旗昨景最望未末札材" ++
-           "束松果栄案梅械極標機欠歴残殺毒氏民求治法" ++
-           "泣浅浴清満漁灯無然焼照熱牧特産的省祝票種" ++
-           "積競笑管節粉紀約結給続置老胃脈腸臣航良芸" ++
-           "芽英菜街衣要覚観訓試説課議象貨貯費賞軍輪" ++
-           "辞辺連達選郡量録鏡関陸隊静順願類飛飯養験"
diff --git a/Data/Kanji/Level/SixthQ.hs b/Data/Kanji/Level/SixthQ.hs
deleted file mode 100644
--- a/Data/Kanji/Level/SixthQ.hs
+++ /dev/null
@@ -1,15 +0,0 @@
-module Data.Kanji.Level.SixthQ where 
-
--- | The Kanji unique to Level-6, studied by the end of 5th grade in
--- Japanese elementary schools.
-sixthQ :: [Char]
-sixthQ = "久仏仮件任似余価保修俵個備像再刊判制券則" ++
-         "効務勢厚句可営因団圧在均基報境墓増夢妻婦" ++
-         "容寄富導居属布師常幹序弁張往復徳志応快性" ++
-         "恩情態慣承技招授採接提損支政故敵断旧易暴" ++
-         "条枝査格桜検構武比永河液混減測準演潔災燃" ++
-         "版犯状独率現留略益眼破確示祖禁移程税築精" ++
-         "素経統絶綿総編績織罪群義耕職肥能興舌舎術" ++
-         "衛製複規解設許証評講謝識護豊財貧責貸貿賀" ++
-         "資賛質輸述迷退逆造過適酸鉱銅銭防限険際雑" ++
-         "非預領額飼"
diff --git a/Data/Kanji/Level/TenthQ.hs b/Data/Kanji/Level/TenthQ.hs
deleted file mode 100644
--- a/Data/Kanji/Level/TenthQ.hs
+++ /dev/null
@@ -1,9 +0,0 @@
-module Data.Kanji.Level.TenthQ where 
-
--- | The Kanji unique to Level-10, studied by the end of 1st grade in
--- Japanese elementary schools.
-tenthQ :: [Char]
-tenthQ = "一七三上下中九二五人休先入八六円出力十千" ++
-         "口右名四土夕大天女子字学小山川左年手文日" ++
-         "早月木本村林校森正気水火犬玉王生田男町白" ++
-         "百目石空立竹糸耳花草虫見貝赤足車金雨青音"
diff --git a/Data/Kanji/Level/ThirdQ.hs b/Data/Kanji/Level/ThirdQ.hs
deleted file mode 100644
--- a/Data/Kanji/Level/ThirdQ.hs
+++ /dev/null
@@ -1,20 +0,0 @@
-module Data.Kanji.Level.ThirdQ where 
-
--- | The Kanji unique to Level-3, studied by the end of middle school
--- in Japan.
-thirdQ :: [Char]
-thirdQ = "乏乙了企伏伐伴伸佳侍促倣倹偶催債克免冗冠" ++
-         "凍凝刑削励勘募匠匿卑卓卸厘又双吉吏哀哲啓" ++
-         "喚喫嘱坑埋塊塗墜墨墳墾壇奉契奪如妨姫娯婆" ++
-         "婿嫁嬢孔孤宴審寿封尿岐岳峡崩巧帆帝幻幽廉" ++
-         "廊弧彫徐忌怠怪恨悔悟悦惜愚慈慌慕慨慰憂憎" ++
-         "憩房抑択抽拘掃掌排掛控措掲揚換揺携搾摂撮" ++
-         "擁擦敢斗斤斥施既昇晶暫架某桑棄棋楼概欧欺" ++
-         "殊殴没泌浪湾湿滅滑滝滞漂漏潜潤濫瀬炉炊炎" ++
-         "焦牲犠猟獄甲畔畜疾痘癖硬碑礎祉稚穂穏穫窒" ++
-         "符篤簿籍粋粗粘糧紛紺絞綱緊締緩縛縫繕翻聴" ++
-         "肝胆胎胞脅膜膨芳苗菊華葬藩虐虚蛮衝衰袋裂" ++
-         "裸覆訂託詠該誘請諮諾謀譲豚貫賊賢赦赴超軌" ++
-         "軸辛辱逮遂遇遭遵邦邪郊郭酔酵鋳錠錬錯鍛鎮" ++
-         "鐘閲阻陪陳陵陶隆随隔隻雇零霊顧飽餓駐騎髄" ++
-         "魂魅魔鯨鶏"
diff --git a/Data/Kanji/Levels.hs b/Data/Kanji/Levels.hs
new file mode 100644
--- /dev/null
+++ b/Data/Kanji/Levels.hs
@@ -0,0 +1,170 @@
+-- |
+-- Module    : Data.Kanji.Levels
+-- Copyright : (c) Colin Woodbury, 2015, 2016
+-- License   : GPL3
+-- Maintainer: Colin Woodbury <colingw@gmail.com>
+--
+-- All Kanji from levels 10 to Pre-2.
+
+module Data.Kanji.Levels where
+
+import qualified Data.Set as S
+
+---
+
+-- | The Kanji unique to Level-10, studied by the end of 1st grade in
+-- Japanese elementary schools.
+tenth :: S.Set Char
+tenth = S.fromDistinctAscList $
+  "一七三上下中九二五人休先入八六円出力十千" ++
+  "口右名四土夕大天女子字学小山川左年手文日" ++
+  "早月木本村林校森正気水火犬玉王生田男町白" ++
+  "百目石空立竹糸耳花草虫見貝赤足車金雨青音"
+
+-- | The Kanji unique to Level-9, studied by the end of 2nd grade in
+-- Japanese elementary schools.
+ninth :: S.Set Char
+ninth = S.fromDistinctAscList $
+  "万丸交京今会体何作元兄光公内冬刀分切前北" ++
+  "午半南原友古台合同回図国園地場声売夏外多" ++
+  "夜太妹姉室家寺少岩工市帰広店弓引弟弱強当" ++
+  "形後心思戸才教数新方明星春昼時晴曜書朝来" ++
+  "東楽歌止歩母毎毛池汽活海点父牛理用画番直" ++
+  "矢知社秋科答算米紙細組絵線羽考聞肉自船色" ++
+  "茶行西親角言計記話語読谷買走近通週道遠里" ++
+  "野長門間雪雲電頭顔風食首馬高魚鳥鳴麦黄黒"
+
+-- | The Kanji unique to Level-8, studied by the end of 3rd grade in
+-- Japanese elementary schools.
+eighth :: S.Set Char
+eighth = S.fromDistinctAscList $
+  "丁世両主乗予事仕他代住使係倍全具写列助勉" ++
+  "動勝化区医去反取受号向君味命和品員商問坂" ++
+  "央始委守安定実客宮宿寒対局屋岸島州帳平幸" ++
+  "度庫庭式役待急息悪悲想意感所打投拾持指放" ++
+  "整旅族昔昭暑暗曲有服期板柱根植業様横橋次" ++
+  "歯死氷決油波注泳洋流消深温港湖湯漢炭物球" ++
+  "由申界畑病発登皮皿相県真着短研礼神祭福秒" ++
+  "究章童笛第筆等箱級終緑練羊美習者育苦荷落" ++
+  "葉薬血表詩調談豆負起路身転軽農返追送速進" ++
+  "遊運部都配酒重鉄銀開院陽階集面題飲館駅鼻"
+
+-- | The Kanji unique to Level-7, studied by the end of 4th grade in
+-- Japanese elementary schools.
+seventh :: S.Set Char
+seventh = S.fromDistinctAscList $
+  "不争付令以仲伝位低例便信倉候借停健側働億" ++
+  "兆児共兵典冷初別利刷副功加努労勇包卒協単" ++
+  "博印参史司各告周唱喜器囲固型堂塩士変夫失" ++
+  "好季孫完官害察巣差希席帯底府康建径徒得必" ++
+  "念愛成戦折挙改救敗散料旗昨景最望未末札材" ++
+  "束松果栄案梅械極標機欠歴残殺毒氏民求治法" ++
+  "泣浅浴清満漁灯無然焼照熱牧特産的省祝票種" ++
+  "積競笑管節粉紀約結給続置老胃脈腸臣航良芸" ++
+  "芽英菜街衣要覚観訓試説課議象貨貯費賞軍輪" ++
+  "辞辺連達選郡量録鏡関陸隊静順願類飛飯養験"
+
+-- | The Kanji unique to Level-6, studied by the end of 5th grade in
+-- Japanese elementary schools.
+sixth :: S.Set Char
+sixth = S.fromDistinctAscList $
+  "久仏仮件任似余価保修俵個備像再刊判制券則" ++
+  "効務勢厚句可営因団圧在均基報境墓増夢妻婦" ++
+  "容寄富導居属布師常幹序弁張往復徳志応快性" ++
+  "恩情態慣承技招授採接提損支政故敵断旧易暴" ++
+  "条枝査格桜検構武比永河液混減測準演潔災燃" ++
+  "版犯状独率現留略益眼破確示祖禁移程税築精" ++
+  "素経統絶綿総編績織罪群義耕職肥能興舌舎術" ++
+  "衛製複規解設許証評講謝識護豊財貧責貸貿賀" ++
+  "資賛質輸述迷退逆造過適酸鉱銅銭防限険際雑" ++
+  "非預領額飼"
+
+-- | The Kanji unique to Level-5, studied by the end of 6th grade in
+-- Japanese elementary schools.
+fifth :: S.Set Char
+fifth = S.fromDistinctAscList $
+  "並乱乳亡仁供俳値傷優党冊処刻割創劇勤危卵" ++
+  "厳収后否吸呼善困垂城域奏奮姿存孝宅宇宗宙" ++
+  "宝宣密寸専射将尊就尺届展層己巻幕干幼庁座" ++
+  "延律従忘忠憲我批担拝拡捨探推揮操敬映晩暖" ++
+  "暮朗机枚染株棒模権樹欲段沿泉洗派済源潮激" ++
+  "灰熟片班異疑痛皇盛盟看砂磁私秘穀穴窓筋策" ++
+  "簡糖系紅納純絹縦縮署翌聖肺背胸脳腹臓臨至" ++
+  "若著蒸蔵蚕衆裁装裏補視覧討訪訳詞誌認誕誠" ++
+  "誤論諸警貴賃遺郵郷針鋼閉閣降陛除障難革頂" ++
+  "骨"
+
+-- | The Kanji unique to Level-4, studied during middle school in Japan.
+fourth :: S.Set Char
+fourth = S.fromDistinctAscList $
+  "丈与丘丹乾互井介仰伺依侵俗倒偉傍傾僧儀兼" ++
+  "冒凡凶刈到刺剣剤劣勧匹占即却及叫召吐含吹" ++
+  "咲唐嘆噴圏坊執堅堤塔壁壊壱奇奥奴妙姓威娘" ++
+  "婚寂寝尋尽尾屈峠峰巡巨帽幅幾床弐弾彩影彼" ++
+  "征御微徴忙怒怖恋恐恒恥恵悩惑惨慎慢慮憶戒" ++
+  "戯扇払扱抗抜抱抵押拍拓拠振捕掘描握援搬摘" ++
+  "撃攻敏敷斜旨旬是普暇暦曇更替朱朽杯枯柄柔" ++
+  "桃欄歓歳殖殿汗汚沈沖沢沼況泊浜浮浸涙淡添" ++
+  "渡溶滴漫澄濁濃為烈煙煮燥爆狂狩狭猛獣獲玄" ++
+  "珍環甘畳疲療皆盆盗監盤盾眠瞬矛砲祈秀称稲" ++
+  "稿突端箇範粒紋紫紹絡継維網緯縁繁繰罰翼耐" ++
+  "肩肪胴脂脚脱腐腕腰膚致舗舞舟般芋芝茂荒菓" ++
+  "蓄薄薪被襲触訴詰詳誇誉謡豪販賦贈越趣距跡" ++
+  "跳踊踏躍軒較載輝輩込迎迫逃透途遅違遣避郎" ++
+  "釈鈍鉛鋭鎖鑑闘陣陰隠隣隷雄雅雌離雷需震霧" ++
+  "露響項頼飾香駆騒驚髪鬼鮮麗黙鼓齢"
+
+-- | The Kanji unique to Level-3, studied by the end of middle school
+-- in Japan.
+third :: S.Set Char
+third = S.fromDistinctAscList $
+  "乏乙了企伏伐伴伸佳侍促倣倹偶催債克免冗冠" ++
+  "凍凝刑削励勘募匠匿卑卓卸厘又双吉吏哀哲啓" ++
+  "喚喫嘱坑埋塊塗墜墨墳墾壇奉契奪如妨姫娯婆" ++
+  "婿嫁嬢孔孤宴審寿封尿岐岳峡崩巧帆帝幻幽廉" ++
+  "廊弧彫徐忌怠怪恨悔悟悦惜愚慈慌慕慨慰憂憎" ++
+  "憩房抑択抽拘掃掌排掛控措掲揚換揺携搾摂撮" ++
+  "擁擦敢斗斤斥施既昇晶暫架某桑棄棋楼概欧欺" ++
+  "殊殴没泌浪湾湿滅滑滝滞漂漏潜潤濫瀬炉炊炎" ++
+  "焦牲犠猟獄甲畔畜疾痘癖硬碑礎祉稚穂穏穫窒" ++
+  "符篤簿籍粋粗粘糧紛紺絞綱緊締緩縛縫繕翻聴" ++
+  "肝胆胎胞脅膜膨芳苗菊華葬藩虐虚蛮衝衰袋裂" ++
+  "裸覆訂託詠該誘請諮諾謀譲豚貫賊賢赦赴超軌" ++
+  "軸辛辱逮遂遇遭遵邦邪郊郭酔酵鋳錠錬錯鍛鎮" ++
+  "鐘閲阻陪陳陵陶隆随隔隻雇零霊顧飽餓駐騎髄" ++
+  "魂魅魔鯨鶏"
+
+-- | The Kanji unique to Level-Pre2, considerend "mid high school" level.
+preSecond :: S.Set Char
+preSecond = S.fromDistinctAscList $
+  "且丙亜享亭仙伯但佐併侮侯俊俸倫偏偵偽傑傘" ++
+  "僕僚儒償充准凸凹刃剖剛剰劾勅勲升厄叔叙吟" ++
+  "呈呉唆唇唯喝喪嗣嚇囚坪垣培堀堕堪塀塁塑塚" ++
+  "塾壌壮奔奨妃妄妊妥姻娠媒嫌嫡宜宰宵寛寡寧" ++
+  "寮尉尚尼履屯岬崇崎帥幣庶庸廃廷弊弔弦彰循" ++
+  "徹忍恭悠患悼惰愁愉慶憤憾懇懐懲懸戻扉扶抄" ++
+  "把披抹拐拒拙括拷挑挟挿捜据搭摩撤撲擬斉斎" ++
+  "旋昆暁曹朕朴杉析枠枢柳栓核栽桟棚棟棺槽款" ++
+  "殉殻汁江沸泡泥泰洞津洪浄浦涯涼淑渇渉渋渓" ++
+  "渦溝滋漆漠漬漸潟濯煩爵猫献猶猿珠琴璽瓶甚" ++
+  "畝疎疫症痢痴癒盲眺睡督矯砕硝硫碁磨礁祥禅" ++
+  "禍租秩稼窃窮窯竜筒粛粧糾紡索累紳緒縄繊繭" ++
+  "缶罷羅翁耗肌肖肢肯臭舶艇艦茎荘菌薦薫藻虜" ++
+  "虞蚊蛇蛍融衡衷裕褐褒襟覇訟診詐詔誓諭謁謄" ++
+  "謙謹譜貞貢賄賓賜賠購践軟轄迅迭逐逓逝逸遍" ++
+  "遮遷還邸酌酢酪酬酷醜醸釣鈴鉢銃銘閑閥附陥" ++
+  "隅雰霜靴韻頑頒頻顕飢駄騰麻"
+
+-- | The Kanji unique to Level-2, considered "standard adult" level.
+second :: S.Set Char
+second = S.fromDistinctAscList $
+  "串丼乞亀伎侶俺傲僅冥冶凄刹剥勃勾匂叱呂呪" ++
+  "咽哺唄唾喉喩嗅嘲埼堆塞填奈妖妬媛嫉宛尻岡" ++
+  "崖嵐巾弄弥彙怨恣惧慄憧憬戚戴拉拭拳拶挨挫" ++
+  "捉捗捻摯斑斬旦旺昧曖曽枕柵柿栃桁梗梨椅椎" ++
+  "楷毀氾汎汰沃沙淫湧溺潰煎熊爪爽牙狙玩瑠璃" ++
+  "璧瓦畏畿痕痩瘍眉睦瞭瞳稽窟箋箸籠綻緻罵羞" ++
+  "羨肘股脇脊腎腫腺膝膳臆臼舷艶芯苛茨萎葛蓋" ++
+  "蔑蔽藍藤虎虹蜂蜜袖裾訃詣詮誰諦諧謎貌貪貼" ++
+  "賂賭踪蹴辣遜遡那酎醒采釜錦錮鍋鍵鎌闇阜阪" ++
+  "隙韓頃須頓頬顎餅餌駒骸鬱鶴鹿麓麺"
diff --git a/Data/Kanji/Types.hs b/Data/Kanji/Types.hs
--- a/Data/Kanji/Types.hs
+++ b/Data/Kanji/Types.hs
@@ -6,13 +6,13 @@
 -- License   : GPL3
 -- Maintainer: Colin Woodbury <colingw@gmail.com>
 --
--- Types for this library.
+-- Types for this library. Note that typeclass instances for `ByteString`s
+-- are not provided, as `SB.pack` garbles characters above 0xFF.
 
 module Data.Kanji.Types where
 
-import qualified Data.ByteString.Char8 as SB
-import qualified Data.ByteString.Lazy.Char8 as LB
 import           Data.Char (ord)
+import           Data.Kanji.Types.Internal ()
 import           Data.Maybe (fromJust)
 import qualified Data.Set as S
 import qualified Data.Text as ST
@@ -30,9 +30,6 @@
   -- minimal complete definition.
   _Kanji :: Traversal' a Kanji
 
-  -- | How long is this input source?
-  len :: Num b => a -> b
-
   -- | Transform this string type into a list of Kanji. The source string
   -- and the resulting list might not have the same length, if there
   -- were `Char` in the source that did not fall within the legal
@@ -42,37 +39,19 @@
 
 instance AsKanji Char where
   _Kanji f c = if isKanji c then _kanji <$> f (Kanji c) else pure c
-
-  len = const 1
+  {-# INLINE _Kanji #-}
 
 instance AsKanji [Char] where
   _Kanji = traverse . _Kanji
-
-  len = fromIntegral . length
+  {-# INLINE _Kanji #-}
 
 instance AsKanji ST.Text where
-  _Kanji = packed . _Kanji
-    where packed f b = ST.pack <$> f (ST.unpack b)
-
-  len = fromIntegral . ST.length
+  _Kanji = each . _Kanji
+  {-# INLINE _Kanji #-}
 
 instance AsKanji LT.Text where
-  _Kanji = packed . _Kanji
-    where packed f b = LT.pack <$> f (LT.unpack b)
-
-  len = fromIntegral . LT.length
-
-instance AsKanji SB.ByteString where
-  _Kanji = packed . _Kanji
-    where packed f b = SB.pack <$> f (SB.unpack b)
-
-  len = fromIntegral . SB.length
-
-instance AsKanji LB.ByteString where
-  _Kanji = packed . _Kanji
-    where packed f b = LB.pack <$> f (LB.unpack b)
-
-  len = fromIntegral . LB.length          
+  _Kanji = each . _Kanji
+  {-# INLINE _Kanji #-}
 
 -- | A single symbol of Kanji. Japanese Kanji were borrowed from China
 -- over several waves during the past millenium. Japan names 2136 of
diff --git a/Data/Kanji/Types/Internal.hs b/Data/Kanji/Types/Internal.hs
new file mode 100644
--- /dev/null
+++ b/Data/Kanji/Types/Internal.hs
@@ -0,0 +1,58 @@
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE UndecidableInstances #-}
+
+-- |
+-- Module    : Data.Kanji.Types.Internal
+-- Copyright : (c) Colin Woodbury, 2015, 2016
+-- License   : GPL3
+-- Maintainer: Colin Woodbury <colingw@gmail.com>
+--
+-- Instances needed for using `each` over `Text` types.
+-- This code is borrowed from `microlens-platform`:
+-- http://hackage.haskell.org/package/microlens-platform
+
+module Data.Kanji.Types.Internal () where
+
+import           Data.Monoid (Endo)
+import qualified Data.Text as T
+import qualified Data.Text.Lazy as TL
+import           Lens.Micro
+import           Lens.Micro.Internal
+
+---
+
+instance (a ~ Char, b ~ Char) => Each T.Text T.Text a b where
+  each = strictText
+  {-# INLINE each #-}
+
+instance (a ~ Char, b ~ Char) => Each TL.Text TL.Text a b where
+  each = lazyText
+  {-# INLINE each #-}
+
+strictUnpacked :: Lens' T.Text String
+strictUnpacked f t = T.pack <$> f (T.unpack t)
+{-# INLINE strictUnpacked #-}
+
+strictText :: Traversal' T.Text Char
+strictText = strictUnpacked . traversed
+{-# INLINE [0] strictText #-}
+
+{-# RULES
+"strict text -> map"    strictText = sets T.map        :: ASetter' T.Text Char;
+"strict text -> foldr"  strictText = foldring T.foldr  :: Getting (Endo r) T.Text Char;
+  #-}
+
+lazyUnpacked :: Lens' TL.Text String
+lazyUnpacked f t = TL.pack <$> f (TL.unpack t)
+{-# INLINE lazyUnpacked #-}
+
+lazyText :: Traversal' TL.Text Char
+lazyText = lazyUnpacked . traversed
+{-# INLINE [0] lazyText #-}
+
+{-# RULES
+"lazy text -> map"    lazyText = sets TL.map        :: ASetter' TL.Text Char;
+"lazy text -> foldr"  lazyText = foldring TL.foldr  :: Getting (Endo r) TL.Text Char;
+  #-}
diff --git a/kanji.cabal b/kanji.cabal
--- a/kanji.cabal
+++ b/kanji.cabal
@@ -1,7 +1,7 @@
 name:                kanji
-version:             1.0.0
-synopsis:            Perform 漢字検定 (National Kanji Exam) level analysis on Japanese Kanji.
-description:         Perform 漢字検定 (National Kanji Exam) level analysis on Japanese Kanji.        
+version:             2.0.0
+synopsis:            Perform 漢字検定 (Japan Kanji Aptitude Test) level analysis on Japanese Kanji.
+description:         Perform 漢字検定 (Japan Kanji Aptitude Test) level analysis on Japanese Kanji.        
 license:             GPL-3
 license-file:        LICENSE
 author:              Colin Woodbury
@@ -17,17 +17,10 @@
 library
   exposed-modules:     Data.Kanji
                      , Data.Kanji.Types
-                     , Data.Kanji.Level.NinthQ
-                     , Data.Kanji.Level.EighthQ
-                     , Data.Kanji.Level.SecondQ
-                     , Data.Kanji.Level.TenthQ
-                     , Data.Kanji.Level.FifthQ
-                     , Data.Kanji.Level.SixthQ
-                     , Data.Kanji.Level.SeventhQ
-                     , Data.Kanji.Level.ThirdQ
-                     , Data.Kanji.Level.FourthQ
-                     , Data.Kanji.Level.PreSecondQ
-  -- other-modules:       
+                     , Data.Kanji.Levels
+
+  other-modules:       Data.Kanji.Types.Internal
+
   other-extensions:    FlexibleInstances
 
   build-depends:       base >= 4.8 && < 4.9
@@ -38,3 +31,5 @@
 
   -- hs-source-dirs:      
   default-language:    Haskell2010
+
+  ghc-options: -O2