Comparison

Kioku vs PIECE

Price, ratings, monetisation and update history for both apps, side by side โ€” with what reviewers say about each.

Head to head
About

Kioku

Features
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Spaced is a flashcard app that uses spaced repetition to help you memorize words, phrases, and knowledge efficiently for the long term. KEY FEATURES โ—† FSRS Algorithm The world-leading memory model "FSRS" analyzes your retention in real time and suggests reviews only when you're about to forget โ€” maximizing results in minimum time. โ—† Auto Dictionary Lookup (Multilingual) Just type a word and tap the dictionary button โ€” pronunciation, meanings, and examples are filled in automatically. Displayed in your device language: Japanese, Korean, Chinese, Spanish, French, German, Portuguese, or English. โ—† Text-to-Speech Tap any word or example sentence to hear native pronunciation. Build your listening skills at the same time. โ—† Organize with Decks Create decks by topic โ€” English vocab, certifications, technical terms โ€” and focus on exactly what you want to study. โ—† Simple to Use Front side for the question, back for the answer. Flip the card and rate yourself: Again / Hard / Good / Easy. Your rating determines when you'll see the card next. โ—† Track Your Progress Monitor retention rate, review count, and study streak on your dashboard. See your daily progress at a glance. โ—† Passwordless Login Sign in securely with just your email and a one-time code. Cards sync automatically across all your devices. WHO IT'S FOR โ€ข English learners and exam preppers (TOEIC, EIKEN, etc.) โ€ข Students studying for medical, legal, or IT certifications โ€ข Anyone building vocabulary in a foreign language โ€ข Students preparing for school or cram school exams PRICING Core features are free to use.

About

PIECE

Features
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ๅ‚่€ƒๆ›ธใฎ็›ฎๆฌกใฎ1่กŒใ‚’ใ€1ๅ›žใงใ“ใชใ›ใ‚‹ใ€Œใƒ”ใƒผใ‚นใ€ใซใ™ใ‚‹ใ€‚ ๆ•™ๆใ”ใจใฎๆตใ‚Œใงใ€ไธŠใ‹ใ‚‰้ †ใซ้€ฒใ‚ใฆใ„ใใŸใ‚ใฎใ‚ฟใ‚นใ‚ฏ็ฎก็†ใงใ™ใ€‚ โ–  ็›ฎๆฌกใ‚’ๆ’ฎใ‚‹ใจใ€่กŒใŒใใฎใพใพใƒ”ใƒผใ‚นใซใชใ‚‹ ๅ‚่€ƒๆ›ธใฎ็›ฎๆฌกใ‚’ๆ’ฎใ‚‹ใจใ€็ซ ใจ็ฏ€ใ‚’่ชญใฟๅ–ใฃใฆใใฎใพใพไธฆในใพใ™ใ€‚ ่กŒใฎ1ใค1ใคใŒใƒ”ใƒผใ‚นใงใ€็ซ ใฎใพใจใพใ‚Šใ‚’ใƒ”ใƒผใ‚นใซใ™ใ‚‹ใ“ใจใ‚‚ใ€ ใใฎไธ‹ใฎ้ …็›ฎใ ใ‘ใ‚’ใƒ”ใƒผใ‚นใซใ™ใ‚‹ใ“ใจใ‚‚ใงใใพใ™ใ€‚ ่ชญใฟๅ–ใฃใŸใ‚ใจใซๆ‰“ใก็›ดใ™ใƒป้ †็•ชใ‚’ๅ…ฅใ‚Œๆ›ฟใˆใ‚‹ใƒป่กŒใ‚’่ถณใ™ใƒปๅˆ†ใ‘ใ‚‹ใŒใงใใพใ™ใ€‚ ๆ’ฎใ‚‰ใšใซๆ‰‹ใงๅ…ฅใ‚Œใ‚‹ใ“ใจใ‚‚ใงใใพใ™ใ€‚ โ–  ๆ•™ๆใ”ใจใฎๆตใ‚Œใง้€ฒใ‚€ ้–‹ใใจใ€ๆ•™ๆใ”ใจใฎๆตใ‚ŒใŒไธฆใณใพใ™ใ€‚ ไธŠใŒ็ต‚ใˆใŸใถใ‚“ใ€ใใฎไธ‹ใŒ้€ฒใ‚ใฆใ„ใ‚‹ใถใ‚“ใ€ใ•ใ‚‰ใซไธ‹ใŒใ“ใ‚Œใ‹ใ‚‰ใฎใ‚‚ใฎใงใ™ใ€‚ ใƒ”ใƒผใ‚นใ‚’ๆŠผใ—ใฆใ€Œๅง‹ใ‚ใ‚‹ใ€ใ€็ต‚ใˆใŸใ‚‰ใ€ŒๅฎŒไบ†ใซใ™ใ‚‹ใ€ใ€‚ 1ๆžšใŒๅคงใใ™ใŽใŸใ‚‰ใ€ใใฎๅ ดใงไฝ•ๆžšใ‹ใซๅˆ†ใ‘ใ‚‰ใ‚Œใพใ™ใ€‚ ใ‚ขใƒ—ใƒชใŒๅ‹ๆ‰‹ใซ้‡ใ‚’ๆฑบใ‚ใ‚‹ใ“ใจใฏใ‚ใ‚Šใพใ›ใ‚“ใ€‚ๅคงใใ•ใ‚’ๆฑบใ‚ใ‚‹ใฎใฏใ‚ใชใŸใงใ™ใ€‚ โ–  ๆœŸ้™ใฏไป˜ใ‘ใฆใ‚‚ไป˜ใ‘ใชใใฆใ‚‚ใ„ใ„ ๆ—ฅไป˜ใ‚’ๆฑบใ‚ใชใใฆใ‚‚ใ€ใƒ”ใƒผใ‚นใฏๅง‹ใ‚ใ‚‰ใ‚Œใพใ™ใ€‚ ๆœŸ้™ใ‚’ไป˜ใ‘ใ‚‹ใจๆœญใซๆ—ฅไป˜ใŒๅ‡บใฆใ€ๆฎ‹ใ‚Šใฏใ€Œ-3ๆ—ฅใ€ใ€้ŽใŽใŸใถใ‚“ใฏใ€Œ+8ๆ—ฅใ€ใง่ฆ‹ใˆใพใ™ใ€‚ ๆœŸ้™ใ‚’ไป˜ใ‘ใŸๆ—ฅใฎๆœใซ้€š็ŸฅใŒๅฑŠใใพใ™๏ผˆ่จญๅฎšใงๅˆ‡ใ‚Œใพใ™๏ผ‰ใ€‚ ๆ‰‹ใ‚’ๆญขใ‚ใ‚‹ใจใใฏใ€Œไผ‘ๆญขใ™ใ‚‹ใ€ใงใ€ใพใ ๆ‰‹ใ‚’ไป˜ใ‘ใฆใ„ใชใ„็Šถๆ…‹ใซๆˆปใ›ใพใ™ใ€‚ โ–  ไฝ•ๅ‘จใ‹ใ™ใ‚‹ๆ•™ๆ 1ๅ‘จใง็ต‚ใ‚ใ‚‰ใชใ„ๆ•™ๆใฏใ€ใƒ”ใƒผใ‚นใ‚’1ๆžš็ต‚ใˆใ‚‹ใŸใณใซๆฌกใฎๅ‘จใฎ1ๆžšใŒ็”จๆ„ใ•ใ‚Œใพใ™ใ€‚ 1ๅ‘จใถใ‚“ใ‚’ๅ…จ้ƒจ็ต‚ใˆใฆใ‹ใ‚‰ใพใจใ‚ใฆๆฌกใฎๅ‘จใซ้€ฒใ‚€ๅฝขใ‚‚้ธในใพใ™ใ€‚ ็›ฎๆจ™ใฎๅ‘จๅ›žใฏๆ•™ๆใ”ใจใซๆฑบใ‚ใ‚‰ใ‚Œใพใ™ใ€‚ โ–  ใƒ”ใƒผใ‚นใ”ใจใซ้›†ไธญใ‚’่จˆใ‚‹ 25ๅˆ†ใฎใ‚ฟใ‚คใƒžใƒผใ‚’ใ€ใ„ใพ้€ฒใ‚ใฆใ„ใ‚‹ใƒ”ใƒผใ‚นใซ็ตใณใคใ‘ใฆๅ›žใ›ใพใ™ใ€‚ ๆฎ‹ใ‚‹ใฎใฏๅ›žๆ•ฐใจใ„ใ†ไบ‹ๅฎŸใ ใ‘ใงใ€ๆ™‚้–“ใ‹ใ‚‰้€ฒใฟๅ…ทๅˆใ‚’ๆŽจๅฎšใ™ใ‚‹ใ“ใจใฏใ—ใพใ›ใ‚“ใ€‚ ใ‚ฟใ‚คใƒžใƒผใ‚’ไฝฟใ‚ใชใใฆใ‚‚ใ€ๅฎŒไบ†ใฏ่จ˜้Œฒใ•ใ‚Œใพใ™ใ€‚ โ–  AIใซ็›ธ่ซ‡ใงใใ‚‹ ็™ป้Œฒใ—ใŸๆ•™ๆใƒปใƒ”ใƒผใ‚นใƒปๆœŸ้™ใƒปใ“ใ‚Œใพใงใฎ่จ˜้Œฒใƒปๅฟ—ๆœ›ๆ กใƒปๆจก่ฉฆใ‚’่ฆ‹ใŸใ†ใˆใงใ€ ๆ–‡็ซ ใง็›ธ่ซ‡ใงใใพใ™ใ€‚่ถณใ‚Šใชใ„ใ“ใจใŒใ‚ใ‚Œใฐ่žใ่ฟ”ใ—ใฆใใพใ™ใ€‚ ๆœŸ้™ใ‚’ๅค‰ใˆใ‚‹ๆๆกˆใฏใ€ๅฏพ่ฑกใจๅค‰ๆ›ดๅ‰ๅพŒใŒไธ€่ฆงใงๅ‡บใพใ™ใ€‚ ๅๆ˜ ใ•ใ‚Œใ‚‹ใฎใฏใ€ๅ†…ๅฎนใ‚’็ขบใ‹ใ‚ใฆใ€ŒๅฎŸ่กŒใ™ใ‚‹ใ€ใ‚’ๆŠผใ—ใŸใจใใ ใ‘ใงใ™ใ€‚ ๅๆ˜ ใ—ใŸใ‚ใจใ‹ใ‚‰ๅ–ใ‚Šๆถˆใ›ใพใ™ใ€‚ไผš่ฉฑใฏใ‚ใจใง่ชญใฟ่ฟ”ใ›ใพใ™ใ€‚ ๅ‹ๆ‰‹ใซๆœŸ้™ใ‚„่จ˜้Œฒใ‚’ๆ›ธใๆ›ใˆใ‚‹ใ“ใจใฏใ‚ใ‚Šใพใ›ใ‚“ใ€‚ โ–  ่จญ่จˆใฎ็ด„ๆŸ ใƒปใ‚ขใƒ—ใƒชใฏ้กใงใ‚ใฃใฆ่ญฆๅ ฑๅ™จใงใฏใ‚ใ‚Šใพใ›ใ‚“ใ€‚้…ใ‚Œใฏๆ—ฅๆ•ฐใงๅฐใ•ใๅ‡บใ™ใ ใ‘ใงใ™ ใƒปๆ‰€่ฆๆ™‚้–“ใ‚„้”ๆˆ่ฆ‹่พผใฟใ‚’ๆŽจๅฎšใ—ใพใ›ใ‚“ใ€‚ไบ‹ๅฎŸใ ใ‘ใ‚’่กจ็คบใ—ใพใ™ ใƒป็…ฝใ‚‰ใšใ€็‚นๆ•ฐใ‚‚็ด„ๆŸใ—ใพใ›ใ‚“ ใ‚ขใƒ—ใƒชๅ†…่ชฒ้‡‘ใซใคใ„ใฆ: AIใธใฎ็›ธ่ซ‡ใจ็›ฎๆฌกใฎ่ชญใฟๅ–ใ‚Šใซใฏใ€Œใƒใ‚ฑใƒƒใƒˆใ€ใ‚’ไฝฟใ„ใพใ™ใ€‚ ็›ธ่ซ‡ใฏใ€1ๅ›žใฎ็›ธ่ซ‡ใงไฝฟใ†ไธŠ้™ใ‚’ๆฑบใ‚ใฆใ‹ใ‚‰ๅง‹ใ‚ใพใ™ใ€‚ ใฏใ˜ใ‚ใฏ3ๆžšใงใ€1ๆžšใ‹ใ‚‰100ๆžšใพใง่‡ชๅˆ†ใงๅค‰ใˆใ‚‰ใ‚Œใพใ™ใ€‚ ๆธ›ใ‚‹ใฎใฏๅฎŸ้š›ใซไฝฟใฃใŸๅˆ†ใ ใ‘ใงใ€ไธŠ้™ใ‚’่ถ…ใˆใฆไฝฟใ†ใ“ใจใฏใ‚ใ‚Šใพใ›ใ‚“ใ€‚ ็ญ”ใˆใŒๅฑŠใ‹ใชใ‹ใฃใŸใ‚„ใ‚Šๅ–ใ‚Šใงใฏๆธ›ใ‚Šใพใ›ใ‚“ใ€‚ ็›ฎๆฌกใฎ่ชญใฟๅ–ใ‚Šใฏใ€่ชญใฟๅ–ใ‚ŒใŸใƒšใƒผใ‚ธ1ๆžšใซใคใ1ๆžšใงใ™ใ€‚ ๆœ€ๅˆใซ10ๆžšใ‚’ใŠๆธกใ—ใ—ใพใ™ใ€‚ใƒใ‚ฑใƒƒใƒˆใฎ่ฟฝๅŠ ่ณผๅ…ฅใฏ่ฒทใ„ๅˆ‡ใ‚Šใงใ™ใ€‚

Screenshots

Kioku4 screens
PIECE4 screens

Verdict

The call

The clearest difference is in-app purchases: PIECE at none against Kioku's 1. Kioku's advantage is iOS requirement (15.1 vs 17.0). On price, ads and device support there is nothing between them.

Scored on Price ยท Rating ยท Positive reviews ยท Number of ratings ยท Update frequency ยท Ads ยท In-app purchases ยท Monetization ยท Best chart rank ยท Devices ยท Requires iOS

CostPrice ยท In-app purchases ยท Ads ยท Monetization

Both are free to download. Kioku sells 1 one-off in-app purchase. PIECE asks for nothing beyond the download.

Scorecard2 real differences ยท 4 level
Kioku versus PIECE: the parameters behind the verdict, then further details
ParameterKiokuPIECE
PriceFreeFree
Update frequencyโ€”Every 3 days
AdsNoNo
In-app purchasesYesNo โ€” better
DevicesiPhone, iPod โ€” betteriPhone
Requires iOS15.1 โ€” better17.0
Further details โ€” not scored
Size33 MB12 MB
Age rating4+4+
DeveloperHIROAKI TANOShuntaro Shimada

In-app purchases

1 purchases

Kioku

One-time1
  • Spaced Premium$1.99
None

PIECE

No in-app purchases

Questions

Is Kioku free?
Kioku is free to download, with in-app purchases available.
Is PIECE free?
PIECE is free to download, with no in-app purchases.
Do Kioku or PIECE have ads?
Neither Kioku nor PIECE shows ads.

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