Only the ace of spades with 〜だけ
Grammar Explanation: Limiting with 〜だけ

The Detective Boys group visits a cabin where Professor Agasa has secretly set out clues leading to a treasure. Conan draws the group’s attention to an arrow pointing to a table, on top of which there is…
- コナン:
- 「これまた不自然に散
( らばったトランプの山( …」- “A pile of cards, rather unnaturally scattered about.”
- 「しかも、なぜかスペードのAだけが画鋲
( でとめてある…」- “Further, for some reason, only the ace of spades is pinned down with thumbtacks...”
- “A pile of cards, rather unnaturally scattered about.”
Key Points
スペードのAだけ = only the ace of spades
Here だけ singles out one card from the scattered pile.
Conan is noticing that only that specific card is being treated differently.
しかも adds “on top of that”
The line builds on the previous observation about the unnatural card pile.
しかも signals an additional suspicious detail.
が marks the card as the thing pinned down
スペードのAだけが 画鋲
( でとめてある means only the ace of spades has been fixed in place with thumbtacks.
See Also
- Kanji: Negation and lack with 不